Egyptian-born cleric Abu Hamza al-Masri has been presented before a federal judge in New York, following his extradition from Britain to face terror charges.
Abu Hamza faces 11 terror charges and is one of five men who left England on Friday, hours after the London High Court ruled they could be extradited "immediately", CNN reported.
Two planes carrying the men left the Royal Air Force base at Mildenhall so they could face trial in the US, British Home Secretary Theresa May said in a statement.
Abu Hamza will be arraigned Tuesday morning, officials said. Separately, Khaled al-Fawwaz and Adel Abdul Bary pleaded not guilty before a judge in London on Saturday.
The trio are being held at New York's Metropolitan Correctional Center in Manhattan, a US federal law enforcement source told CNN.
Two others, Babar Ahmad and Talha Ahsan, clad in green and yellow prison jumpsuits, also pleaded not guilty before a judge in New Haven, Connecticut.
The charges against Abu Hamza include conspiracy in connection with a 1998 kidnapping of 16 Westerners in Yemen, and conspiring with others to establish an Islamic jihad training camp in rural Oregon in 1999. He could be sentenced to life in prison if convicted.
The cases of Ahmad and Ahsan are both linked to a website called azzam.com, which US prosecutors say was run by the two men to support terrorism around the world.
Meanwhile, al-Fawwaz and Bary are accused of being Al Qaeda associates of Osama bin Laden in London during the 1990s.
Abu Hamza is one of the highest-profile radical Islamic figures in Britain, where he was already sentenced to seven years for inciting racial hatred and other terror charges.
He travelled to Britain to study before gaining citizenship through marriage in the 1980s, according to the CNN.
The one-eyed radical preacher has called the 9/11 attacks on the World Trade Center "a towering day in history" and described Osama as "a good guy and a hero".
He also described the Columbia space shuttle disaster in 2003 as "punishment from Allah" because the astronauts were Christian, Hindu and Jewish.