Rebel fighters trying to oust President Bashar Al-Assad shot down a fighter jet as it flew over the northern Syrian town of Atarib in Idlib province, a witness said.
The witness, an independent journalist who asked to remain anonymous, said rebel fighters were attacking a military base near the town when the jet flew over and rebels shot it down with anti-aircraft guns.
Vastly outgunned, rebels say they need surface-to-air missiles to take down planes and helicopters used by the Syrian military to bombard opposition strongholds.
Fighters use outdated anti-aircraft machine guns that are welded to pickup trucks but they are inaccurate and useless if the military aircraft fly above a certain altitude.
On 27 August fighters shot down a helicopter on the outskirts of Damascus and three days later rebels said they had brought down a jet in Idlib, near the Turkish border.
Activists say more than 27,000 people, mostly civilians, have been killed in the 18-month-old revolt in Syria, which began with peaceful street protests that provoked a military crackdown and mushroomed into civil war.
Despite calling for Assad to step down, the West is wary of arming disparate rebel groups.