A Bangladeshi man has pleaded guilty to attempting to use a weapon of mass destruction in what authorities called a plot to blow up the New York Federal Reserve Bank.
He faces up to life in prison under a plea agreement.
Quazi Mohammad Rezwanul Ahsan Nafis, 21, was arrested on 17 October after he attempting to detonate what he believed to be a 1,000lb (454kg) bomb hidden in a van.
Instead, he was carrying inert materials planted by an undercover FBI agent as part of a sting operation.
"I no longer support violent jihad. I deeply regret my involvement in this case," Mr Nafis said at the hearing.
Mr Nafis had also been charged with a count of attempting to provide material support to a US-designated foreign terrorist organization, al-Qaeda.
His lawyer said that charge would be dropped at sentencing under the plea agreement, which sets a sentencing range between 30 years and life.
Sentencing was set for 30 May.
According to a criminal complaint unsealed in October, Mr Nafis entered the US in 2012 with a student visa, and eventually travelled to Queens, New York.
There, he scouted targets for a potential attack - including the New York Stock Exchange and US President Barack Obama - settling eventually on the Federal Reserve Bank in Manhattan, the complaint said.
He attempted to recruit others to his plot, and discussed his plans over social media sites such as Facebook, the complaint said.
He claimed he was in contact with al-Qaeda operatives overseas and actively sought out new al-Qaeda connections in the US.
One of the individuals he brought on board was an undercover agent working for the FBI, who monitored Mr Nafis' activities and helped arm him with the inoperable explosives, federal authorities said.
Prosecutors said Mr Nafis attempted to use a mobile phone to detonate the explosives, which were concealed in a van.
After Mr Nafis repeatedly tried and failed to trigger the explosives, he was arrested, authorities said.
"As today's guilty plea shows, the defendant came to this country not to further his studies, but to advance the goal of jihad," US Attorney Loretta Lynch said in a statement.
"With diligence and determination, Nafis attempted to carry out his plan in the name of al-Qaeda."
Following the hearing, a lawyer for Mr Nafis, Heidi Cesare, said he "pleaded guilty because he is guilty, and wants to take responsibility for that."