A U.S. Marine who disappeared in Iraq and was feared to have been kidnapped said Monday that he did not desert the military.

Cpl. Wassef Ali Hassoun (search), who resurfaced in Lebanon nearly three weeks after he went missing, told reporters outside Qauntico Marine Corps Base (search) in Virginia that he had been captured.

"I did not desert my post," Hassoun said. "I was captured and held against my will by anti-coalition forces for 19 days. This was a very difficult and challenging time for me."

Hassoun did not answer any questions during his brief appearance. He was joined by his brother, who had recently arrived at Quantico from Utah.

"I would like to tell all the Marines as well as all those others serving in Iraq to keep their heads up and spirits high. Once a Marine, always a Marine, Semper Fi," Hassoun said, invoking the Marine Corps motto, Latin for "always faithful."

Marine spokesman Lt. Col. Dave Lapan said the Marine Corps was not in a position to confirm or refute Hassoun's claim.

"We're not in a position to make a judgment either way," Lapan said.

Hassoun is in the midst of what the Marines call a "repatriation process" in which he is debriefed and given time to decompress and avoid the media spotlight, Marine Corps officials said.

"When we determine exactly what happened to him, he'll either receive medals or severe punishment, there will be no in-between," one U.S. military official told FOX News.

In the coming days, Hassoun will leave Quantico for Camp Lejeune, N.C., his home base, where he will continue the repatriation process, Lapan said.

FOX News has learned that Hassoun has not been in handcuffs since military officials met him in Beirut and that now he has escorts assigned to him 24 hours a day, but he is not considered to be in custody.

Lapan said the Marine Corps reviewed Hassoun's statement and made no changes.

Hassoun thanked God and friends and family for their support. "I understand that there are many questions and respectfully ask that the media respect my need to spend private time with my family," he said.

Lapan said that Hassoun has expressed no reservations about returning to active duty.

One military official told FOX News that Hassoun "demonstrates the pride of a Marine corporal and says he's anxious to get back to his duties."

Hassoun arrived at Quantico on Friday after six days of medical evaluation at a military hospital in Germany. Marine officials said it may be weeks or months until Hassoun returns to active duty.

Hassoun, 24, of West Jordan, Utah, had been missing since June 20 from his base near the troubled Iraqi city of Fallujah before turning up unharmed at the U.S. Embassy in Beirut July 8. It remains unclear how he traveled from Iraq to Lebanon, where he was born and still has relatives.

On June 27, Arab television showed a videotape of Hassoun with his eyes covered by a white blindfold and a sword hanging over his head.

At one point during his disappearance, a group claiming to represent his captors falsely claimed that he had been beheaded after being lured from the base by a love affair.

The Navy is investigating whether the kidnapping might have been a ruse. But the Naval Criminal Investigation Service (search ) is not expected to question Hassoun until his repatriation procedure is completed, the Marine Corps said.

FOX News' Rita Cosby and The Associated Press contributed to this report.