The Russian President Vladimir Putin has said the Boston Marathon bombing justifies his tough line on insurgents in the North Caucasus.
Speaking as he answered questions in his annual “hotline” dial-in live on television, he said Russia and the US should step up cooperation on security.
“Russia is a victim of international terrorism, one of the first victims. I urge strongly that this tragedy bring us closer together, in stopping the threats we have in common, the most dangerous being terrorism.”
Putin, who crushed a Chechen bid for independence over a decade ago, has long accused the US of underestimating the Islamist threat.
In the Russian region of Dagestan the mother of the Boston suspects has said she is considering whether to join their father, who wants to visit the US to bury his son. Tamerlan Tsarnaev was killed after a shoot-out with police.
Reports say Zubeidat Tsarnaeva was charged with shoplifting in Boston last summer and could face arrest if she returns.