A Bangladeshi man snared in an FBI terror sting considered targeting U.S. President Barack Obama and the New York Stock Exchange before settling on a car bomb attack on the Federal Reserve, just blocks from the World Trade Center site, a law enforcement official told The Associated Press on Thursday.

The official, who was not authorized to speak publicly about the investigation and talked to the AP on condition of anonymity, stressed that the suspect never got beyond the discussion stage in considering an attack on the president.

In a September meeting with an undercover agent posing as a fellow jihadist, Quazi Mohammad Rezwanul Ahsan Nafis explained he chose the Federal Reserve as his car bomb target "for operational reasons," according to a criminal complaint. Nafis also indicated he knew that choice would "cause a large number of civilian casualties, including women and children," the complaint said.

The bomb was phony, but authorities said that Nafis' admiration of Osama bin Laden and aspirations for martyrdom were not.

FBI agents grabbed the 21-year-old Nafis — armed with a cellphone he believed was rigged as a detonator — after he made several attempts to blow up a fake 454-kilogram bomb inside a vehicle parked next to the Federal Reserve Wednesday in lower Manhattan, the complaint said.

Nafis appeared in federal court in Brooklyn on Wednesday to face charges of attempting to use a weapon of mass destruction and attempting to provide material support to al-Qaeda. Wearing a brown T-shirt and black jeans, he was ordered held without bail and did not enter a plea. His defense attorney had no comment outside court.

Family stunned

Nafis is a banker's son from a middle-class neighbourhood, and family members said Thursday that they were stunned by his arrest.

"My son can't do it," his father, Quazi Ahsanullah, said as he wept in his home in the Jatrabari neighborhood in north Dhaka, Bangladesh.

"He is very gentle and devoted to his studies," he said, pointing to Nafis' time at the private North South University in Dhaka.

However, Belal Ahmed, a spokesman for the university, said Nafis was a terrible student who was put on probation and threatened with expulsion if he didn't bring his grades up. Nafis eventually just stopped coming to school, Ahmed said.

Ahsanullah said his son convinced him to send him to America to study, arguing that with a U.S. degree he had a better chance at success in Bangladesh.

"I spent all my savings to send him to America," he said.

Arrived in January

He arrived in January on a student visa and studied for one semester at Southeast Missouri State University, but requested a records transfer in January and the university did not know why. Apparently, he instead decided to plot an attack, reaching out for possible conspirators who turned out to be government agents, authorities said.

This image taken from the Google Plus site shows an undated photo of Quazi Mohammad Rezwanul Ahsan Nafis, the man accused of plotting to detonate a bomb outside the Federal Reserve building in New York City. This image taken from the Google Plus site shows an undated photo of Quazi Mohammad Rezwanul Ahsan Nafis, the man accused of plotting to detonate a bomb outside the Federal Reserve building in New York City. (Associated Press)

He had sought assurances from one undercover, posing as an al-Qaeda contact, that the terrorist group would support the operation.

"The thing that I want to do, ask you about, is that, the thing I'm doing, it's under al-Qaeda?" he was recorded saying during a meeting in a bugged hotel room in Queens, according to the complaint.

Later, Nafis "confirmed he was ready to kill himself during the course of the attack, but indicated he wanted to return to Bangladesh to see his family one last time to set his affairs in order," the complaint said.

But there was no allegation that Nafis actually received training or direction from the terrorist group.

The Federal Reserve is one of the most fortified buildings in the city, smack in the middle of a massive security effort headed by the New York Police Department, where a network of thousands of private and police cameras watch for suspicious activity.

Obama will be in New York City on Thursday night. He will appear with Republican challenger Mitt Romney at the Alfred E. Smith Memorial Foundation Dinner, an annual political event.