Federal agents have arrested a Pakistani American who US officials say was plotting terrorist attacks on Washington’s metro transit system. Farooque Ahmed (34) of Ashburn, Virginia, was arrested on Wednesday for attempting to assist others, whom he believed to be members of Al-Qaida, in planning multiple bombings at Metrorail stations in the Washington DC area.

"Farooque Ahmed is accused of plotting with individuals he believed were terrorists to bomb our transit system, but a coordinated law enforcement and intelligence effort was able to thwart his plans," said David Kris, assistant attorney general for national security.

US Attorney Neil H. MacBride said it was “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." But US officials said the public was never in danger and that the FBI was aware of Ahmed’s activities from before the alleged attempt began and closely monitored his activities until his arrest. The simultaneous attacks were planned for 2011.

Ahmed is the second Pakistani American in the recent months to be arrested for allegedly plotting terrorist attacks in the U.S. Faisal Shahzad, the other Pakistani American, was sentenced to life in prison this month for his role in a plot to set off a car bomb in New York City’s busy Times Square.

On Tuesday, a federal grand jury in Alexandria, Virginia, returned a three-count indictment against Ahmed, a naturalised U.S. citizen born in Pakistan, charging him with attempting to provide material support to a designated terrorist organisation, collecting information to assist in planning a terrorist attack on a transit facility, and attempting to provide material support to help carry out multiple bombings to cause mass casualties in the DC-area Metrorail stations. If convicted, Ahmed faces a maximum penalty of 50 years in prison.

According to the indictment, from April 2010 through October 25, 2010, Ahmed attempted to assist others whom he believed to be members of Al-Qaida in planning multiple bombings to cause mass casualties at Metrorail stations. On or about May 15, 2010, at a hotel in Herndon, Virginia, Ahmed allegedly agreed to watch and photograph a hotel in Washington DC and a Metrorail station in Arlington, Virginia, to obtain information about their security and busiest periods.