The Russian authorities have been "very co-operative" with the United States since the Boston marathon bombings just over two weeks ago, President Barack Obama said.
Mr Obama has spoken to Russian president Vladimir Putin as US law enforcement agencies investigate whether bombing suspect Tamerlan Tsarnaev met radical Muslim militants on a six-month trip to the Russian region of Dagestan last year ahead of allegedly bombing the marathon on April 15th.
The president indicated that there was still a hangover of distrust between the US and Russia from the tensions of previous decades.
“Old habits die hard,” he said. “There are still suspicions sometime between our intelligence and law enforcement agencies that date back 10, 20, 30 years, back to the Cold war, but they’re continually improving all the time.”
Mr Obama has asked his counterterrorist advisers to examine what more could be done to detect threats from “self-radicalised individuals”. Americans were not going to be intimidated by “warped, twisted individuals,” he said.
US federal agents are investigating possible links between Tamerlan Tsarnaev, the dead older brother of the two men suspected of the bombings, and a Canadian boxer-turner-jihadist William Plotnikov. Tsarnaev ended a six-month visit to Dagestan, returning to the US days just after Plotnikov and six others died in a gun battle with Russian forces in July 2012. Simon Carswell