Updated

A California man pleaded guilty Friday to a federal terrorism charge after admitting he attempted to assist Al Qaeda by providing weapons training, the U.S. attorney's office said.

Sinh Vinh Ngo Nguyen, 24, of Garden Grove entered the plea before U.S. District Court Judge John F. Walter, who scheduled sentencing for March 21, prosecutors said in a statement. Nguyen faces a maximum of 15 years in federal prison.

The statement said Nguyen's admission was contained in a plea agreement filed in federal court.

"Nguyen admitted that approximately one year ago he traveled to Syria where he joined opposition forces," the statement said. "Using a social network site during a four-month period he was in Syria, Nguyen told people that he was fighting against the Assad regime and that he had had a `confirmed kill."'

Nguyen returned to the U.S., where he told associates that he had offered to train Al Qaeda forces in Syria but was turned down, the U.S. attorney's office said.

Prosecutors said that between Aug. 3 and Oct. 11 Nguyen met with a man he thought was an Al Qaeda recruiter but who actually was working for the FBI, telling him about what he'd done in Syria and saying he wanted to return to jihad.

On Oct. 1, Nguyen purchased a ticket for travel from Mexico to Pakistan and he was arrested by FBI agents on Oct. 11 as he was about to board a bus from Santa Ana, Calif., to Mexico.