By Elise Labott
BRUSSELS (CNN) - When Secretary of State John Kerry meets Tuesday with Russian Foreign Minister Sergei Lavrov on the sidelines of NATO meetings, he will have a full agenda, starting with the crisis in Syria, disarmament talks with Iran and nuclear saber rattling by North Korea.
There also will be the issue of missile defense and ongoing negotiations between Moscow and Washington to make drastic cuts in their respective nuclear arsenals.
But the Chechen roots of the Boston Marathon bombing suspects will loom large.
While Russia could be helpful in tracing possible motivation of the alleged attackers, brothers Dzhokhar and Tamerlan Tsarnaev, as well as any possible connection to terrorist groups, the Obama administration wants to make sure it does not upset an already fragile relationship.
The deadly Boston attack last Monday could potentially complicate U.S. efforts to get Russian support for outside intervention in Syria. Russia staunchly opposes any action by the U.N. Security Council and continues to arm the Syrian regime.
Washington and Moscow also remain at odds over the administration's plans to place American missile defense systems in Eastern Europe. Last week President Barack Obama's national security adviser, Tom Donilon, traveled to Moscow but didn't make much progress on getting Russian agreement on the proposal.
Russia's human rights record has also stood in the way of better ties.
Most recently the Obama administration published a blacklist of alleged human rights abusers in Russia as part of the Magnitsky Act, a U.S. law that has strained relations.
It imposes visa bans and freezes assets of those believed responsible for the death of Russian lawyer Sergei Magnitsky, an attorney who uncovered the largest tax fraud in the country's history. He was beaten to death in 2009 after a year in a Moscow detention center.
The blacklist also includes an individual accused in the 2006 shooting death of a Chechen man who filed claims against Moscow with the European Court for Human Rights in Strasbourg for alleged rights violations in Chechnya.
Moscow blasted the legislation as a political ploy and an interference in the affairs of a sovereign state. Following congressional action, Putin signed a Russian law banning Americans from adopting Russian orphans. The foreign ministry has also drawn up its own list of U.S. officials it accuses of committing human rights violations.
Counterterrorism, however, has been one of the better areas of cooperation between the two countries since the 2001 al Qaeda attacks on the United States.
The revelation that Russian intelligence services asked the FBI to investigate Tamerlan Tsarnaev, 26, in 2011 over a possible association with terror groups illustrates intelligence sharing. But it remains to be seen whether a larger blame game ensues around questions relating to follow up.
The Senate Intelligence Committee is examining the role of the FBI in the matter.
In a development late on Monday, Dzhokhar Tsarnaev, 19, has told investigators his older brother was the driving force behind the attack and that no international terrorist groups were behind them, a U.S. government source said on Monday.
Meanwhile, its possible Russia could use any connections the bombers may have had to justify its crackdown on radical Muslim groups in Chechnya and the neighboring Russian republic of Dagestan.
Russia is preparing for the 2014 Winter Olympics in Sochi, which his near the Caucuses, and is likely to work to eliminate any terror threats.
The United States has supported Russia's fight against terrorist groups, but has voiced concern about its overly aggressive methods and its tendency to treat all separatists as terrorists linked to al Qaeda.
While the Boston bombings could offer an opportunity for stronger cooperation between Washington and Moscow, Cory Welt of the Center for American Progress preaches a more realistic approach.
"While we should welcome greater U.S.-Russian counterterrorism cooperation, we should also temper expectations that the United States and Russia will develop entirely convergent policies of counterterrorism and counterextremism-or that such cooperation will be sufficient to overcome the still-substantial challenges in U.S.-Russian relations," Welt said.
A call between Obama and Russian President Vladimir Putin shortly after the Boston attack illustrates this point.
In a statement after the call, the White House praised counterterrorism cooperation with Russia, including after the bombings. But the Kremlin went further, saying the two leaders agreed to step up cooperation in the field.
"Both sides underlined their interest in deepening the close cooperation of the Russian and U.S. special services in the fight against international terrorism," the Kremlin statement said.
Kerry, a former Massachusetts senator, has been reluctant to say anything about the suspects in Boston - Tamerlan Tsarnaev died after a shootout with police last Thursday, while his brother was captured the next day and criminally charged on Monday.
When asked last week whether the attack validates Russia's views on Chechnya, Kerry would only say "terror is terror."
"Terror anywhere in the world, against any country, is unacceptable," Kerry told reporters. "And we need to continue to stand up and fight against it. And we need to continue to stand up and fight against it in the way that we are."