The United States and Russia on Monday agreed to widen their security cooperation in the wake of the Boston Marathon bombing, DPA reported.
The decision came during a telephone conversation between Presidents Vladimir Putin and Barack Obama, who agreed to share more intelligence on terrorism suspects, Putin's foreign policy aide Yuri Ushakov said, the Interfax news agency reported.
The main suspects in the April 15 attack, brothers Tamerlan and Dzhokhar Tsarnaev, have their roots in the Russian North Caucasus.
Putin's spokesman Dmitry Peskov denied that Russia withheld information about them from the United States by saying that the brothers had not lived in Russia for a long time.
Media reports suggest that the brothers moved to the United States at around 2002.
The elder brother Tamerlan, who was killed in a shootout with police, is believed to have spent up to six months last year in Dagestan and Chechnya, two Russian Caucasus republics suffering from a violent Islamist insurgency.