Quazi Mohammad Rezwanul Ahsan Nafism, a 21-year-old man, has been arrested on suspicion of planning to blow up the Federal Reserve Bank of New York, federal officials said. Authorities say he attempted to detonate what he believed was a 1000-pound bomb. The plot came to light as an FBI undercover agent posed as an al-Qaeda facilitator, federal authorities say. Nafis asked the undercover agent for 50-pound bags of what he thought were explosives, and then worked on putting together an explosive device, according to prosecutors. “Nafis purchased components for the bomb’s detonator and conducted surveillance for his attack on multiple occasions in New York City’s financial district in lower Manhattan,” a Justice Department press release describing the criminal complaint said. “Throughout his interactions with the undercover agent, Nafis repeatedly asserted that the plan was his own and was the reason he had come to the United States.” Nafis appeared to have had a back-up plan. He met an undercover agent that supplied him with what he thought were explosives on Wednesday morning. After meeting up, they both traveled in a van to a warehouse, the Justice Department said. That’s apparently when Nafis told the agent he had a “Plan B.” If Nafis felt his attack was about to be thwarted by cops, he would invoke the back-up plan, which involved a suicide bombing operation, the criminal complaint alleges. When the pair arrived at the warehouse, Nafis began putting together what he <b>…</b>