A PAKISTANI-AMERICAN man has been arrested for planning attacks on subway stations in and around Washington DC with people he believed were associated with al Qaeda, according to the US Department of Justice.

Farooque Ahmed, 34, had allegedly been casing and photographing subway stations around the city since April 2010. Ahmed, a naturalised American citizen living in the Virginia suburbs of Washington, allegedly planned to conduct simultaneous bombings.

David Kris, assistant attorney general for national security said that “a co-ordinated law enforcement and intelligence effort was able to thwart his plans”.

The White House has insisted that President Barack Obama had been aware of Ahmed and his alleged plot since before the arrest, and that the American public was never in any danger.

The FBI and national security officials had been on working on the case “from the beginning” according to White House spokesman Robert Gibbs, who added: “At no point was the public in any danger”.

A federal grand jury returned a three-count indictment against Ahmed on Tuesday

Ahmed was due to appear in a court in Virginia Wednesday to face charges of attempting to provide material support to a terrorist organisation, collecting information to assist in planning a terrorist attack, and attempting to provide help to carry out multiple bombings and cause mass casualties in Washington.

CNN quote an unnamed official as saying Ahmed has no known connections to any overseas terrorist groups or individuals.

He could be jailed for up to 50 years if convicted.

“It’s chilling that a man from Ashburn is accused of casing rail stations with the goal of killing as many Metro riders as possible through simultaneous bomb attacks,” said US Attorney Neil MacBride.