Alexandria, Virginia (CNN) -- Farooque Ahmed, accused of helping what he thought was an attempt to bomb Metro stations in the Washington area last year, pleaded guilty to two charges Monday in U.S. District Court.
He was immediately sentenced to 23 years in prison.
Ahmed had pleaded not guilty last year. In changing his plea, he admitted that he attempted to provide material support to a designated terrorist organization. He also pleaded guilty to collecting information to assist in planning a terrorist attack on a transit facility.