Plans for 9/11 anniversary attack uncovered
Computer files seized during the raid on Osama bin Laden's hideout show al Qaida were planning a "spectacular" attack on trains in the US on September 11, 2011, the tenth anniversary of the 9/11 tragedy.
The terrorist network is thought to have been planning to tamper with tracks so that a train would be derailed while crossing a bridge or valley, potentially killing hundreds of passengers.
The plan, developed in February last year, was disclosed by the US Department of Homeland Security (DHS), which issued a warning about it to law enforcement agencies around the US.
"We wanted to make our partners aware of the alleged plotting," Matthew Chandler, a DHS spokesman, said on Thursday night. "It is unclear if any further planning has been conducted".
The plot is said to have been in the "aspirational", rather than "operational" stages. No specific locations had been selected. But it will intensify long-standing fears that this year's tenth anniversary of the September 11 attacks will attract new threats.
The DHS said since Sunday's raid it had sent more officers to protect American airports and reviewed "protective measures for all potential terrorist targets", including the entire US transport system.
It is also considering "new targeting rules" to help them identify "the risk of both passengers and cargo coming to the United States," Mr Chandler said.
The plot emerged as sources said the CIA could read details of senior al Qaida leaders on the so-called "treasure trove" of computer files, because they were not encrypted.