A Turkish jet that crashed in June was downed after a Syrian missile exploded nearby in international airspace, the army said Wednesday, three months after an incident that heightened tensions between the two neighbours.

The probe by the army prosecutor into the downing of the two-seater F4 Phantom found that it crashed into the eastern Mediterranean after a Syrian missile exploded near its rearside, the army said in a statement.

The final report says the Turkish plane fell "due to the blast effect that incapacitated the pilots and the plane," causing a dramatic loss of altitude. The two pilots aboard were killed.

The report reiterates Turkey's official position that the plane was shot down in international airspace, a claim rejected by Damascus.

In July, Syrian President Bashar al-Assad told a Turkish newspaper that he regretted that his country's defence forces shot down the jet, but insisted the plane was in Syrian airspace at the time.

The army prosecutors said there was no trace of anti-aircraft ammunition on the wreckage retrieved from the water after the incident, rejecting Damascus's claim.

The June 22 incident exacerbated tensions between the one-time allies, with Ankara vowing a harsh response to any border violations by Syria, and both sides have sent military reinforcements to the frontier.

Some media reports, including in the international press, say the plane was in Syrian airspace and was shot down by shore-based anti-aircraft guns after the Turkish jet provoked Syrian air defences.

But Turkish officials have repeatedly disputed the reports, insisting the plane was brought down by surface-to-air missiles, which have longer ranges and can strike down the aircraft in international airspace.