The Russian and U.S. presidents have agreed by telephone to increase cooperation on counter-terrorism following the Boston Marathon bombings, the Kremlin said on Saturday.
The White House said President Barack Obama had thanked President Vladimir Putin for Russia's close cooperation on counter-terrorism after the bombing, which U.S. officials suspect was carried out by two ethnic Chechens who once lived in Russia.
"President Putin expressed his condolences on behalf of the Russian people for the tragic loss of life in Boston," the White House said in a statement.
It said Obama had praised cooperation with Russia on counter-terrorism, including after Monday's bombing. The Kremlin appeared to go further, saying the two leaders had agreed they should now step up their work together in this 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," it said, but gave no details.
Putin has not commented on the identity of the two suspects, ethnic Chechen brothers who moved to the United States more than a decade ago after briefly living in Russia's volatile southern region of Dagestan.
Tamerlan Tsarnaev was shot dead by police and his brother Dzhokhar was captured after a manhunt.
Kremlin spokesman Dmitry Peskov said on Friday Putin had repeatedly made clear that Russia condemned all acts of terror, regardless of who carried them out.