An American supporter of al-Qaeda has pleaded guilty to trying to blow up the Pentagon and US Capitol with explosives-laden remote-controlled model planes.
US citizen Rezwan Ferdaus, 26, was arrested after a sting operation in which federal officers posed as al-Qaeda members to supply explosives.
Prosecutors and defence lawyers agreed to recommend a 17-year jail term.
Ferdaus had been planning "jihad" since 2010, according to prosecutors.
He pleaded guilty to two charges: attempting to supply materials to al-Qaeda, and seeking to damage US government buildings with explosives.
Ferdaus said he would accept the 17 years' imprisonment term under a plea deal with the prosecution. He could have faced 35 years for the two charges together if the case had gone to trial.
Under the deal, prosecutors agreed to drop four of the original six charges.
Members of his family present in court were reported to have been distraught.
Ferdaus, born in Massachusetts to parents of Bangladeshi descent, is a physics graduate of Northeastern University in Boston.
He was arrested in the city last September after an elaborate undercover investigation by the FBI lasting several months, officials say.
Ferdaus began planning "jihad" (holy war) against the United States in 2010 after jihadist websites and videos convinced him the United States was evil, prosecutors told the Associated Press.
Believing the undercover FBI agents were al-Qaeda members, Ferdaus told them about his plan to organise an attack on the Pentagon, home of the US military, and the Capitol building in Washington DC, seat of the US Congress, prosecutors said.
He described the Pentagon as "the head and heart of the snake" and said he was targeting the "enemies of Allah", according to an affidavit released by the US Justice Department at the time of his arrest.
Asked about the possibility of killing women and children, Mr Ferdaus allegedly said all non-followers of Islam were his enemies.
The FBI agents then supplied him with grenades, six machine guns and plastic explosives, according to the authorities. He is also said to have obtained a remote-controlled plane up to 2m (7ft) in length that could be guided by GPS and fly at 100mph (160km/h).
In June 2011, he allegedly travelled to Washington on a surveillance trip.
The weapons were always under control of the agents and were never a threat to the public, according to prosecutors.
Ferdaus had also plotted to target US soldiers in Iraq and Afghanistan using improvised explosive devices, according to the prosecution.
In 2011, he allegedly supplied the FBI operatives with 12 mobile phone detonators intended to be used by al-Qaeda operatives to set off bombs in the Middle East.