A Yemeni national has pleaded guilty in a U.S. federal court in New York of conspiring to murder Americans and of providing material support to a terrorism organization.

According to court papers, Saddiq al-Abbadi left Yemen for Iraq to fight against U.S. troops from late 2005 to early 2007.

Yemeni Man Pleads Guilty of Conspiring With al-Qaida

In early 2008, he traveled to northwestern Pakistan to fight for al-Qaida before slipping across the border into Afghanistan to fight U.S. troops.

Yemeni Man Pleads Guilty of Conspiring With al-Qaida

Prosecutors said Abbadi also used his connections to help an American from Long Island, Bryant Neal Vinas, join al-Qaida. Vinas pleaded guilty in 2009 of helping al-Qaida plan an attack on the Long Island Rail Road. He was arrested before he could carry out the attack.

Yemeni Man Pleads Guilty of Conspiring With al-Qaida

Acting U.S. Attorney Kelly Currie said in a statement Tuesday that Abbadi "was a high-level al-Qaida operative with ties to the terrorist group’s senior leadership in both Pakistan and Yemen.”

Abbadi could face a maximum sentence of life in an American prison. His sentencing is scheduled for September.