NEW YORK (CNN) -- A 21-year-old foreign exchange student who authorities say tried to blow up New York's Federal Reserve Bank was indicted Thursday on charges of using 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 a 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, allegedly inspired by al Qaeda, 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, but authorities say he claimed that the plot was his own and was his sole motivation for the U.S. trip.

A U.S. District Court grand jury in New York charged Nafis with trying to use a bomb as a weapon of mass destruction and trying to provide explosives and communications equipment to al Qaeda terrorists, the indictment says.

In Bangladesh, Nafis graduated from high school in 2006 and took his higher secondary school certificate examinations in 2008 before he enrolled in the country's leading private university, North South University, in Dhaka, documents say.

Nafis traveled to the United States with "the purpose of conducting a terrorist attack" and actively sought out al Qaeda contacts after his arrival, authorities in New York allege.

He majored in cybersecurity at Southeast Missouri State University from January to May of this year, a university spokeswoman said. At the end of the spring semester, he was elected vice president of the Muslim Student Association, but his term was short-lived because he left the campus, the spokeswoman said.

His father, Quazi Mohammad Ahsanullah, has said that he can't believe the terrorist accusations and that his son is timid person who's often scared to travel alone.

The father, a banker in Dhaka, said his son left college in Missouri after one semester because of the expense and went to New York, where he worked 10-hour days at a hotel.

In the sting operation, Nafis apparently contacted an FBI source and proposed multiple targets, including a high-ranking U.S. official and the New York Stock Exchange, authorities said.

Nafis indicated that he wanted to "destroy America" by going after the nation's financial institutions and ultimately settled on the landmark bank in Manhattan, authorities said.

An undercover agent, authorities say, also provided 20 bags of purported explosives, weighing 50 pounds each, to Nafis, who then stored the material in a warehouse in preparation for the strike.

Authorities alleged that Nafis further divulged a "Plan B" that involved carrying out a suicide attack should police thwart his initial effort.

Packing his van with what he apparently believed were explosives, Nafis then allegedly traveled with the undercover agent to Manhattan's financial district, attached a detonator to the material and recorded a video statement in a nearby hotel before he was eventually arrested, authorities said.

CNN's Susan Candiotti and Michael Martinez contributed to this report.

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