MIAMI: Two Pakistani-born brothers accused in a plot to detonate a bomb in New York City to avenge the deaths of people killed by drone attacks in Afghanistan, pleaded guilty to federal terrorism charges on Thursday in Miami.

Raees Alam Qazi, 22, and Sheheryar Alam Qazi, 32, were arrested in 2012, accused of providing support to al Qaeda to use a weapon of mass destruction.

The brothers are naturalised US citizens who were living in Fort Lauderdale, Florida at the time of their arrest.

The younger brother pleaded guilty on Thursday to conspiring and attempting to provide material support to terrorists and conspiring to assault a federal employee. He faces a maximum sentence of 35 years in prison followed by supervised release for life.

His older brother also pleaded guilty to conspiring to provide material support to terrorists as well as conspiring to assault a federal employee. He faces a maximum sentence of 20 years in prison followed by supervised release for life.

Sentencing was set for June 5.

“The plot was intended to further al Qaeda's message in the United States,” said the US attorney for south Florida, Wifredo Ferrer.

He went on to say, “this case serves as an example of our commitment to protecting civilians from violent jihadi attacks.”

Both pleaded not guilty after their initial arrest and were denied bail after a judge considered them a flight risk.

Raees Alam Qazi traveled to New York in November 2012 with the hope of finding a job to make enough money to build an explosive, according to court testimony from an FBI agent.

The younger Qazi told investigators after his arrest that he rode around New York on a bike looking for targets but never chose one and returned home four days later after running out of money, prosecutor Karen Gilbert said.

His older brother, a cab driver, was accused by prosecutors with supporting the plot, paying bills, providing a computer and a cellphone.

During recorded phone calls, Raees Alam Qazi asked about the size of crowds at Times Square, Wall Street and at some New York theaters, the FBI said.

In a search of the house where Raees Alam Qazi was living, authorities say they recovered a laptop computer that showed he had researched ingredients to make a shoe bomb.