(CNN) - A 21-year old foreign exchange student who tried to blow up New York's Federal Reserve Bank was indicted Thursday for attempting to use a weapon of mass destruction and trying to provide material support to al Qaeda.

Quazi Mohammad Rezwanul Ahsan Nafis, a Bangladeshi national, was arrested by federal authorities in sting operation in October. He was accused of trying to detonate what he thought was a 1,000-pound bomb by using his cell phone as a trigger. The bomb was inert.

Nafis was allegedly inspired by al Qaeda and came to the United States in January on a student visa under the pretext of attending college at Southeast Missouri State University, prosecutors said.

It's not clear whether Nafis maintained al Qaeda ties, authorities said, but he apparently claimed that the plot was his own and was his sole motivation for the U.S. trip.