Syrian rebel fighters appear to have used a surface-to-air missile to shoot down an Assad regime helicopter this week, raising questions about how they obtained the advanced weapon and fears it could one day be used by jihadists against civilian aircraft.

Video footage appears to show rebels firing the missile, sometimes known as man-portable air defence systems (Manpads), at a Syrian regime Mi-17 military helicopter during fighting in Idlib on Tuesday. The footage could not be independently confirmed.

The helicopter crashed to the ground in a ball of fire and the bodies of both pilots were found near the village of Qaminas.

Suspicion immediately fell on Turkey as the state most likely to have provided the weapon to its Syrian rebel allies. Turkey cooperates closely with some of the armed groups in Idlib and tensions are running high between Turkey and the Syrian regime over the latter’s offensive in the province.

At least 13 Turkish soldiers have been killed in Syrian regime bombardments in the last month. Recep Tayyip Erdoğan, Turkey’s president, has hinted he would take more aggressive steps against Syrian regime aircraft, saying: “We will use whatever tools necessary on the ground and air, without any hesitation.”