Algerian national Ali Charaf Damache was extradited to the US from Spain last year
An Irish citizen and Algerian national has pleaded guilty in the US to conspiring to provide material support and resources to terrorists.
53-year-old Ali Charaf Damache was indicted on two charges in 2011 in Pennsylvania.
He was extradited from Spain in July 2017.
According to the US Justice Department, Damache and a co-defendant conspired to "support, recruit, and coordinate a terrorist cell" - made up of people from both Europe and the US - "to wage violent jihad" in South Asia and Europe.
Damache is said to have agreed to a "180-month" (15 year) prison sentence as part of his guilty plea, and has waived his right to appeal.
After completing the sentence, he will be returned to either Ireland or Algeria.
FBI Assistant Director in Charge William F Sweeney said: "Damache knowingly and willingly conspired with others to wage a violent jihad overseas, actively supporting the very ideals that allow terrorism to thrive worldwide.
“For as long as there are those who commit to carrying out these intolerable acts, the FBI will resolutely continue to address counterterrorism as our number one priority."
The investigation was led by US law enforcement, with authorities in Ireland and Spain said to have assisted.
Officials say Damache will be formally sentenced on October 30th.