United States officials say a preliminary assessment of computers and hard drives seized at Osama bin Laden's compound show he was plotting fresh attacks on American targets.
The al Qaeda leader, widely believed to be the mastermind of the September 11 terrorist attacks on the United States in 2001, was shot dead in a raid on Sunday by American special forces in Pakistan.
The New York Times is reporting that CIA analysts have found evidence of a plan to attack a train.
According to the newspaper, the US government is revising its view that bin Laden in his final years played a lower profile in al Qaeda's leadership.
It reports that intelligence gathered at his compound in Abbottabad suggests the 54-year-old was communicating with his followers and considering an attack on America's public transport system.
Notes from February last year show bin Laden was interested in blowing a train up as it crossed a railway bridge, though officials say the plan was aspirational rather than fully developed.
The US government has issued a security warning to the operators of America's railways and the CIA is continuing to mine the evidence seized in Pakistan for more information.
Meanwhile, Osama Bin Laden's wife has reportedly told Pakistani interrogators that her husband had not left the room in which he was killed for five years.