BEIRUT, LEBANON - An air force pilot landed his MiG-21 fighter at a Jordanian air base on Thursday, becoming the first Syrian airman to defect with his warplane since the rebellion against President Bashar Assad began 15 months ago.

Jordan granted him political asylum.

The incident was an embarrassment and a symbolic blow to Assad, whose government is locked in a bloody struggle against a determined insurgency.

The Syrian Air Force -- once commanded by Assad's late father, Hafez Assad -- has been regarded as especially loyal to the government.

The state-run Syrian press bureau issued a statement denouncing the pilot, Col. Hassan al-Hamada, as "a deserter and a traitor to his country" who "will be punished accordingly."

The defection came hours after the U.S. ambassador to Syria, Robert Ford, issued the most direct appeal yet to members of the Syrian security forces to abandon the regime and join the opposition. Although there is no indication that the pilot was responding to the appeal, the defection was welcomed in Washington as a further sign of building discontent within the military.

The Syrian pilot took off early Thursday from a base in southern Syria, flying at a high speed and low altitude, reported Al-Jazeera, the pan-Arab satellite network. A source close to the opposition reported that the pilot was a father of five from restive Idlib Province and that his family was under the protection of the Free Syrian Army.