The Russian chief prosecutor's office is to examine whether the Soviet Union acted legally when it recognised the Baltic states' independence in 1991.
The investigation was described as an "absurd provocation" by Lithuania's Foreign Minister Linas Linkevicius.
Estonia, Latvia and Lithuania were occupied by Soviet communist forces in 1940. The USSR broke up in 1991.
Last week Russia's chief prosecutor declared illegal the transfer of Crimea from Russia to Ukraine in 1954.
At the time Russia and Ukraine were republics of the USSR, under communist leader Nikita Khrushchev.
Russia's annexation of Crimea in March 2014 was condemned internationally. Ethnic Russians there voted to rejoin Russia, in a highly controversial referendum.
There are large ethnic Russian minorities in Estonia and Latvia, while Lithuania has a smaller ethnic Russian minority.
Baltic tensions
A source at the prosecutor's office, quoted by Russia's Interfax news agency, said the investigation into the Baltic states' independence followed a request from two parliamentary deputies.
In their letter, MPs Yevgeny Fyodorov and Anton Romanov, of President Vladimir Putin's United Russia party, said the 1991 decision to recognise Baltic independence had been taken "by an unconstitutional body".
The source added that there would not be "legal consequences" if the 1991 recognition of Estonia, Latvia and Lithuania was deemed to be illegal.
The three Baltic states joined the EU and Nato in 2004. In recent years Russia has viewed that as a hostile challenge to its security interests.
Russian-Baltic tensions have been rising since the Crimea annexation and the outbreak of fighting in eastern Ukraine in April 2014. Heavily armed pro-Russian separatists there are clashing daily with Ukrainian government troops.
Nato has stepped up its presence in the Baltic states, responding to massive Russian military exercises, including heightened Russian air force activity in the Baltic.
Reacting to the Russian prosecutor's move, Lithuania's foreign minister called it "a provocation to say the least" and "legally, morally and politically absurd".
The Greek government has requested a new bailout deal from the eurozone, just hours before it must repay €1.6bn (£1.1bn) to the International Monetary Fund (IMF).
Greece is asking for a new two-year €29.1bn aid deal from a bailout mechanism for eurozone countries.
Eurozone finance ministers will discuss the Greek offer in a teleconference on Tuesday evening.
If it fails to make the IMF payment, Greece could risk leaving the euro.
The European Commission, which is one of Greece's creditors, wants Athens to raise taxes and cut welfare spending.
No advanced economy has ever missed a payment on an IMF loan.
Amid fears of a Greek default on its huge public debt of €323bn - and a possible exit from the euro - long queues of people are continuing to snake from many cash machines in Greece, where withdrawals are capped at just €60 a day.
Analysis: By Chris Morris, BBC News, Brussels
Nothing if not dramatic, the Greek government has waited until well past the eleventh hour to request an entirely new third bailout.
It involves borrowing money from the eurozone's permanent bailout fund, the European Stability Mechanism - there is no mention of the IMF. Greece is asking for loans totalling €29.1bn to cover its debt repayments until the end of 2017.
But reaching an agreement on a third bailout could take weeks if not months.
So the letter the Greek government has sent to the ESM and the eurogroup also asks again for an extension to the current bailout - in order to ensure that a technical default is not triggered.
The trouble is that the level of political distrust between Greece and its creditors is so high at the moment that any progress will be difficult to achieve.
Loans from the ESM come with conditions attached - conditions which would include many of the economic and structural reforms that the two sides have been haggling over for months.
But the alternative to yet more talks on finding a deal? A massive step into the unknown for all concerned.
Greek banks did not open this week after talks between Greece and its creditors broke down.
However, up to 1,000 bank branches will re-open from Wednesday to allow pensioners - many of whom do not use bank cards - to withdraw up to €120.
The European Commission offered a slightly amended deal to Greece late on Monday night, which the Greek government did not accept.
Instead, Greece responded with a request for a two-year deal under the European Stability Mechanism (ESM), the bailout mechanism for eurozone countries whose aim is to maintain the stability of the euro.
The ESM did not exist when Greece was bailed out in 2010 and 2012.
Eurozone finance ministers will discuss the offer in a teleconference at 17:00 GMT, Dutch Finance Minister Jeroen Dijsselbloem announced.
However, German Chancellor Angela Merkel has insisted that the eurozone's wealthiest member will not enter into new aid negotiations with Greece before its weekend referendum.
"Before a referendum, as planned, is carried out, we won't negotiate on anything new at all," she said.
A referendum is due to take place in Greece on Sunday over whether the country should accept its creditors' proposals.
EU leaders have warned that a rejection would mean Greece leaving the eurozone - though Mr Tsipras says he does not want this to happen.
The EC says that if funds were to be released, Mr Tsipras and his party must back the "yes" vote in the referendum.
What will happen next?
01:00 Greek time Wednesday (22:00 GMT): Greece's €1.6bn repayment to the IMF is due.
5 July - the referendum on creditors' proposals, and many say Greece's membership of the eurozone, takes place
20 July - Greece must redeem €3.46bn of bonds held by the European Central Bank. If it fails to do so, the ECB can cut off Greece's access to emergency loans.
On Monday Mr Tsipras appealed to Greeks to reject the creditors' proposals, saying this would give Greece "more powerful weapons" in negotiations.
He also hinted that he would resign if the result of the referendum was a "yes" vote.
"If the Greek people want to proceed with austerity plans in perpetuity, which will leave us unable to lift our head... we will respect it, but we will not be the ones to carry it out," he said.
Marusa, attending a No rally on Monday, says: "I believe in Tsipras and I'm not worried"
Meanwhile, European Commission President Jean-Claude Juncker said he felt betrayed by the Tsipras-led government and called on Greek voters to oppose him.
The ECB is believed to have disbursed virtually all of its emergency funds for Greece, amounting to €89bn (£63bn).
Days of turmoil
Queues were forming in front of some ATMs in Athens - but customers will only be allowed to take out €60 per day
Friday evening: Greek prime minister calls referendum on terms of new bailout deal, asks for extension of existing bailout
Saturday evening: Greek parliament backs referendum for 5 July
Sunday afternoon: ECB says it is not increasing emergency assistance to Greece
Sunday evening: Greek government says banks to be closed for the week and cash withdrawals restricted to €60
Is Grexit nearer?
Katya Adler: A European divide
Existential threat to euro from Greek exit
A guide to the key numbers and issues
Lenders' proposals - key sticking points
VAT (sales tax): A new system to come in from 1 July, with three rates, aimed at boosting annual revenue by 1% of total output (GDP)
Most goods to be taxed at top rate of 23%, including restaurants and catering and processed foods
Reduced rate of 13% for basic food, electricity, hotels and water
Super-reduced rate of 6% for medicines, books and theatre
End exemptions and eliminate VAT discounts for Greek islands
Create strong disincentives to early retirement
Move retirement age up to 67 by 2022
End Ekas "solidarity" top-up grant that some 200,000 poorer pensioners get - immediate Ekas cut for wealthiest 20% of recipients, and cut completely by 2020
Pensioners' healthcare contributions to rise to 6%, from 4%
Source: European Commission document, 26 Jun 15 (pdf)
Greek PM Alexis Tsipras has urged voters to reject creditors' demands in a snap referendum on Greece's debt crisis due on Sunday.
Mr Tsipras said a clear vote against austerity would help Greece negotiate a better settlement to the crisis.
Otherwise, he warned, he would not stay in office to oversee more cuts.
Greece's bailout expires on Tuesday, the same day it faces a deadline to repay a €1.6bn (£1.1bn) loan to the International Monetary Fund (IMF).
The loan is to be repaid by 18:00 Washington time (22:00 GMT).
EU leaders have warned that a rejection of the creditors' proposals on Sunday would mean Greece leaving the eurozone - though Mr Tsipras says he does not want this to happen.
Talks between Greece and its creditors broke down last week, leading to Greek banks having to shut this week. The uncertainty also caused stock markets to fall sharply on Monday.
Asian markets rebounded on Tuesday, with stock markets in Tokyo, Hong Kong and Seoul all rising compared with Monday.
Media captionPrime Minister Alexis Tsipras says creditors want to get rid of him
Tens of thousands of people gathered outside the Greek parliament in Athens on Monday evening in a show of support for the government's proposals. A rival protest organised by those calling for a yes vote is due later on Tuesday.
Resignation hint
Speaking live on state TV on Monday evening, Prime Minister Alexis Tsipras appealed to Greeks to reject the creditors' proposals, saying this would give Greece "more powerful weapons" to take to the negotiating table.
"We ask you to reject it with all the might of your soul, with the greatest margin possible," he said.
Marusa, attending a no rally on Monday, says: "I believe in Tsipras and I'm not worried"
He told viewers he did not believe the creditors wanted Greece out of the eurozone "because the cost is immense".
Mr Tsipras also hinted strongly that he would resign if the result of the referendum was a "yes" vote.
"If the Greek people want to proceed with austerity plans in perpetuity, which will leave us unable to lift our head... we will respect it, but we will not be the ones to carry it out," he said.
But some eurozone leaders, including the Italian prime minister and French president, voiced their concern on Monday that Greek voters would effectively be deciding next Sunday whether or not they wanted to stay in the eurozone.
Meanwhile, European Commission President Jean-Claude Juncker said on Monday he felt betrayed by the Tsipras-led government and called on Greek voters to oppose him.
Mr Juncker said that he still believed a Greek exit from the euro was not an option and insisted that the creditors' latest proposals meant more social fairness.
Days of turmoil
Queues were forming in front of some ATMs in Athens - but customers will only be allowed to take out €60 per day
Friday evening: Greek prime minister calls referendum on terms of new bailout deal, asks for extension of existing bailout
Saturday evening: Greek parliament backs referendum for 5 July
Sunday afternoon: ECB says it is not increasing emergency assistance to Greece
Sunday evening: Greek government says banks to be closed for the week and cash withdrawals restricted to €60
Is Grexit nearer?
Katya Adler: A European divide
Existential threat to euro from Greek exit
A guide to the key numbers and issues
The government has already been forced to order all banks to be closed until 6 July after the European Central Bank (ECB) decided not to extend its emergency funding.
The ECB is believed to have disbursed virtually all of its ceiling for funds, amounting to €89bn (£63bn).
Long queues of people were seen snaking outside ATMs on Monday, with withdrawals capped at just €60 a day.
Elderly people, many without bank cards, were seen waiting outside closed bank branches in the hope of getting access to funds.
Referendum question
The question which will be put to voters on Sunday will not be as simple as whether they want to stay in the euro or not - instead it asks Greeks to approve or reject the specific terms laid out by Greece's creditors:
"Should the agreement plan submitted by the European Commission, European Central Bank and the International Monetary Fund to the June 25 eurogroup and consisting of two parts, which form their single proposal, be accepted? The first document is titled 'Reforms for the completion of the Current Program and Beyond' and the second 'Preliminary Debt Sustainability Analysis'.
"Not approved/NO
"Approved/YES"
Trying to crack the puzzle of the Greek referendum question
Greek debt jargon explained
The Athens stock exchange has also been closed as part of the emergency measures.
The government said it would make public transport free in the Athens area for a week while the banks are closed.
On Monday evening the ratings agency Fitch said it had downgraded its rating of four Greek banks, National Bank of Greece, Piraeus Bank, Eurobank Ergasias and Alpha Bank, to "restricted default".
WASHINGTON — The Army has quietly killed a program that put social scientists on battlefields to help troops avoid unnecessary bloodshed and improve civilians' lives, an Army spokesman said Monday.
The initiative, known as the Human Terrain System, had been plagued by fraud and racial and sexual harassment, a USA TODAY investigation found.
HTS, which spent at least $726 million from 2007 to 2014 in Iraq and Afghanistan, was killed last fall, Gregory Mueller, an Army spokesman, said in an email. Commanders in Afghanistan, where the U.S. combat mission ended last year, no longer had a need for the advice of civilian anthropologists.
"The HTS program ended on September 30, 2014, as there was no longer a requirement for HTS teams in theater," Mueller said in a statement.
Several months earlier, Army Secretary John McHugh had praised the program, saying the information the teams provided was "actionable and useful for decision-making."
Social scientists criticized the program from the outset. A key concern for them was the militarization of their field and the potential that their work would be used to target insurgents, a violation of their ethical code not to hurt those they study.
"HTS' termination was long overdue," said Roberto Gonzalez, professor of anthropology at San Jose State University. "Given the many reports of waste, fraud and mismanagement, why did it survive for more than eight years?"
Rep. Duncan Hunter, R-Calif., said, "HTS is a program that had no legitimate application in a war zone or out of one, and the termination of the program was overdue. But it's odd that the program was canceled only after the Army made repeated efforts to defend its use and effectiveness. If anything, the Army's decision shows that HTS is a program our troops can live without, which many of us have known and pointed out.
"Why it was defended and continued in the face of shrinking budgets and alternate priorities is beyond me, but it's good to see the Army step up and do the right thing," Hunter said. "Better late than never."
USA TODAY
Army defends battlefield social science program
Ethical concerns gave way to charges of time-sheet padding and sexual harassment. A USA TODAY investigation of the program uncovered an internal Army investigation in 2010 that had found the Human Terrain System had been "fraught with waste, fraud and abuse."
Some team members, according to documents obtained by USA TODAY, filled out fake time sheets at the urging of supervisors to pad their paychecks. Some members were paid $280,000 per year for work that investigators doubt was done. Team members, who worked as federal government employees, were entitled to six months of paid leave when they returned home.
USA TODAY
Closing the books on combat social scientists
In a survey about their work environment, one team member wrote, "Sexual harassment is prevalent, and sexist behavior is an everyday occurrence; I was sexually harassed in the field repeatedly; sexual comments and jokes are rampant; nearly every female in the program faces some form of sexual harassment."
The Army responded to the allegations of fraud by ordering training for Human Terrain System employees on how to fill out time sheets properly, the documents show. It said sexual harassment is not tolerated, and a contractor found responsible for it was fired.
More consequences for Donald Trump after his comments about Mexican immigrants: NBC dumped his beauty pageants and reiterated he will not be in The Apprentice anymore.
The network, which has been under pressure to fire Trump since last week when Univision announced it would not air Trump's Miss USA pageant in Spanish, said in a statement that "respect and dignity for all people are cornerstones of our values."
"Due to the recent derogatory statements by Donald Trump regarding immigrants, NBC Universal is ending its business relationship with Mr. Trump," the statement said.
"To that end, the annual Miss USA and Miss Universe Pageants, which are part of a joint venture between NBC and Trump, will no longer air on NBC. In addition, as Mr. Trump has already indicated, he will not be participating in The Apprentice on NBC," because he is an announced Republican candidate for president.
"Celebrity Apprentice is licensed from Mark Burnett's United Artists Media Group and that relationship will continue," the network added.
ONPOLITICS
NBC/Universal severs ties with Donald Trump
Trump announced he is running for president two weeks ago in a rambling kick-off speech that included his plans to control illegal immigration: He said he would build a "great wall" and make Mexico pay for it because Mexico is "sending" people who are rapists, drug dealers and criminals, and a few "good people," too.
This proved too much for the leading Spanish-language network, Univision, which serves millions of Mexicans and Mexican Americans in the USA, and had a contract with the Miss Universe organization (Trump is a part-owner) to air the Miss USA pageant on July 12 in Spanish.
But the network declared that Trump's rhetoric about Mexicans (he did not mention other Latino groups or the Canadian border, for instance) was insulting and offensive.
USA TODAY
Univision dumps Miss Universe, blames Trump
Trump, as is his wont, went ballistic, threatened to sue Univision for backing out of an "ironclad" contract, declared he didn't say what he was videotaped saying, and went on multiple political and entertainment shows, besides tweeting, to try to walk back what he said and explain that he really is very fond of Mexicans.
