An accused Al Qaeda sleeper agent who was held on American soil without charges for more than five years has pleaded not guilty to conspiracy and supporting terrorism.

Forty-three-year-old Ali al-Marri appeared Monday in federal court in Peoria, Illinois, where he entered his not guilty plea. He was arrested in Illinois in 2001.

Federal authorities allege the graduate student was an Al Qaeda agent tied to organizers of the Sept. 11, 2001 attacks.

Al-Marri was a legal U.S. resident when he was arrested, but became the only "enemy combatant" in custody on U.S. soil. The native of Qatar was held at a Navy brig in South Carolina.

Al-Marri's case has been transferred to Illinois, where a federal grand jury indicted him.