Haroon Aswat, a 40-year-old who suffers from paranoid schizophrenia, was extradited from Britain to the United States in October, nearly a decade after his 2005 Zambia arrest.
He pleaded guilty to one count of conspiring to provide material support to Al-Qaeda, and one count of actually providing the support to the terror group.
Each charge carries a maximum sentence of 10 years in prison. US prosecutors said he would be deported after serving his term, which will be determined at a later sentencing hearing.
“Haroon Aswat fought his extradition to the United States for almost 10 years,” said US Attorney Preet Bharara.
“He then pled guilty to material support charges within just six months of arriving here, showing again our legal system’s capacity for swift justice.”
According to the indictment, Aswat set up a training camp in Bly, Oregon in the United States between June 2000 and December 2001 for people wanting to go to fight in Afghanistan.
He conspired to do so with Abu Hamza, who was himself extradited to the US and last year convicted on 11 kidnapping and terror charges, and two other suspects.
Aswat was arrested in 2005 in Zambia, extradited to Britain and moved to a psychiatric hospital in 2008 until being sent to the US.
After traveling to Bly, US officials say he spent two months in Seattle living at a mosque where he witnessed men being given additional coaching on how to handle weapons.
They say that documents recovered by FBI agents from a safe house used by 9/11 plotter Khalid Sheikh Mohammed in Pakistan listed a number of individuals associated with Al-Qaeda, including Aswat. -AFP