WASHINGTON -- With authorities identifying two ethnic Chechen brothers as the suspects responsible for the Boston Marathon bombings, the hot-and-cold U.S.-Russian relationship is facing an unexpected twist.
Early in President Obama's first term, his administration proposed a "reset" in the historically complicated relationship with Russia, which resulted in a short warming of relations between the countries.
But over the last few years, the relationship has been soured by a series of policy disagreements -- including differences over the ongoing civil strife in Syria where Russian President Vladimir Putin has opposed the ouster of Bashar Assad, while Obama says the Syrian president must go.
The White House won't give details of any coordination they've had with Russian officials since identifying Tamerlan and Dzhokhar Tsarnaev as the suspects for Monday's blasts in Boston.
But on Friday evening, Obama spoke with Putin and "praised the close cooperation that the United States has received from Russia on counterterrorism, including in the wake of the Boston attack," according to a White House statement.
Even before the Chechen connection surfaced publicly on Friday, Putin condemned the explosions as a "disgusting" crime and offered to help the U.S. investigation in any way he could. On Friday, the suspects' father, who is living in Russia, told CNN that he had been questioned by Russian authorities before being released.
A U.S. law enforcement official, who was not authorized to comment on the investigation, said investigators have been drawn to the overseas travel records of the elder suspect, Tamerlan, who was killed in a firefight with police on Friday morning.
The travel records show that the 26-year-old man left John F. Kennedy International Airport on Jan. 12, 2012, for Sheremetyevo International Airport, near Moscow. The suspect returned to JFK on July 17, 2012, but the purpose of his visit is unclear, the official said. But authorities say they have found no formal links between the suspects and any terrorist groups.
Fiona Hill, a Russia analyst at the Brookings Institution in Washington, said that Putin may angle to "reset the reset" and argue that Obama needs to be more concerned about the Chechen separatists, some of whom have made their way to fighting with Taliban in Afghanistan and the Syrian opposition.
After the 9/11 attacks on the United States, Putin -- who at the time was waging a brutal counterinsurgency effort against separatists in the predominantly Muslim population of Chechnya in southern Russia -- reached out to President Bush in the hopes of collaborating on intelligence efforts and winning the U.S. support for their fight in Chechnya.
"Where the U.S. wanted to talk about Afghanistan, he wanted to talk about Chechnya and have the U.S. turn a blind eye to the human-rights abuses there," Hill said.
The U.S. and Russia coordinated on national security matters in Afghanistan and central Asia in the aftermath of Sept. 11. But the U.S., while it has backed Russia's territorial integrity and supported its right to combat terrorism, has kept an arm's length from Russia's battles in Chechnya.
In recent years, Russia watchers say that cooperation on security matters has diminished as the USA and Russia increasingly find themselves at odds on a host of issues, ranging from the war in Syria to corruption in Moscow.
"There is increasingly a conviction (in Washington) that the Russians continually pick the wrong side, and that when and if it comes to cooperation on national security issues with the United States, we do not want to tip our hands to Moscow because of who they may share information with," said Matt Rojansky, deputy director of the Russia and Eurasia Program at the Carnegie Endowment for International Peace. "The other side is what does Russia have to offer the United States, that it is not offering in return."
Chechnya sought independence after the collapse of the Soviet Union, and subsequently separatist groups fought two bloody wars with the authorities in Moscow.
Militants have also made several high-profile terror attacks in Russia and the North Caucasus region over the years, but have never targeted the United States. In the most high-profile attack, they took over a school in Beslan in the North Ossetia region in 2004. When the siege ended, more than 330 people had died -- half of them children.
Today, violence has been reduced dramatically in Chechnya, but it continues to simmer there and elsewhere in the North Caucasus region.
Russia is hosting the 2014 Winter Olympics in Sochi, near the Black Sea and the Caucasus Mountains, hundreds of miles from Chechnya, and Russian officials remain concerned about security there, analysts say.
"They are keeping tabs on them, and they are pretty darned concerned about them blowing up the Sochi Winter Olympics," Hill said.
Obama and Putin's predecessor, Dmitry Medvedev, started off on the right foot.
In the first year of Obama's presidency, the two nations forged an agreement on nuclear arms treaty and administration officials was pleased with the Russian's backing tougher U.N. Security Council sanctions on Iran.
But the relationship has chilled since Putin returned to power nearly a year ago.
Administration officials raised concerns that Putin was heavy-handed in squashing dissent among the middle-class opposition movement ahead of his inauguration last year, and they expressed displeasure with the prosecution of members of the punk band Pussy Riot, which was critical of Putin.
Putin also ruffled feathers in Washington by canceling long-standing projects in Russia run by the United States Agency for International Development.
In December, Putin retaliated against the U.S. Congress passing a law punishing Russian human rights violators by signing into law a measure prohibiting the adoption of Russian children by U.S. citizens.
But some experts say the Boston tragedy may provide an opportunity for another thawing.
"Certainly, in the past these situations have helped promote reconciliation between the U.S. and Russia," said Jeffrey Mankoff, a Russia analyst at the Center for Strategic and International Studies. "Potentially that could happen again."
Aamer Madhani, USA TODAY
Contributing: Kevin Johnson