The tactic used by the FBI to apprehend Quazi Mohammad Reywanul Ahsan Nafis is one they have used before: an undercover agent appears to provide a suspect with the means to carry out a terror attack, and when the suspect attempts to put the plan into motion, authorities move in.

In the case of Nafis, a 21-year-old Bangladeshi, he attempted to detonate what he thought was a 1,000-pound bomb with a remote control across the street from the Federal Reserve in Manhattan.

Nafis now faces charges of attempting to use a weapon of mass destruction and lending material support to al Qaeda.

According a statement from the US Attorney's Office, Nafis came to the United States in January "for the purpose of conducting a terrorist attack on US soil." He claimed he had connections to al Qaeda, and also tried to recruit people inside the US to join a terrorist cell.

One of these people Nafis attempted to recruit was an informant for the FBI, the statement said.

From then on, as Nafis put together a plan to carry out a terror attack, he was being closely monitored by law enforcement officials.

Nafis apparently considered several targets before settling on the Federal Reserve Bank, which houses one of the largest stores of gold in the world.

An undercover FBI agent gave Nafis what he thought were explosives to be used in the attack. On Wednesday morning, Nafis and the undercover agent parked a van full of the purported explosives in front of the Federal Reserve. When he attempted to detonate the bomb, he was arrested.

"The defendant thought he was striking a blow to the American economy," said US Attorney Loretta Lynch. "He thought he was directing confederates and fellow believers. At every turn, he was wrong, and his extensive efforts to strike at the heart of the nation's financial system were foiled by effective law enforcement."

"Attempting to destroy a landmark building and kill or maim untold numbers of innocent bystanders is about as serious as the imagination can conjure," said FBI acting assistant director-in-charge Mary Galligan, adding that at no point was the public in danger. "The defendant faces appropriately severe consequences."

If convicted, Nafis could receive a life sentence.

mz/jm (Reuters, dpa, AP)