Turkish leaders observed a moment of silence at the funeral of two pilots of a fighter jet shot down by Syria last month in an incident that has escalated tensions between the two former allies.

Turkish Prime Minister Recep Tayyip Erdogan interrupted his vacation to attend the ceremony at the Erhac airbase, from which the F-4 Phantom took off before Syrian defence forces downed it over the Mediterranean sea on June 22.

Televised images showed coffins draped with the national flag at the ceremony, two days after the Turkish army recovered the pilots' bodies at the bottom of the Mediterranean sea.

Also present at the ceremony were ministers from Erdogan's government and army Chief-of-Staff General Necdet Ozel.

Turkey maintains its plane was shot down in international airspace, but Syrian President Bashar al-Assad insisted Tuesday the plane was in Syrian airspace at the time.

But he has said he regretted the incident.

The incident further exacerbated tensions between the two countries, which have deteriorated since the Syrian revolt erupted in March 2011.

Erdogan has repeatedly denounced the Syrian conflict, calling it a repression orchestrated by Syrian forces, and has called for al-Assad to step down.

Assad, in an interview published in Turkish daily Cumhuriyet Thursday, accused Turkey of giving logistical backing to Syrian "terrorists" and told Ankara to stop meddling in his country's affairs.

Turkey has denied reports that it has been supplying arms to Syrian opposition forces.

Since the jet was shot down, Ankara has changed its rules of engagement and vowed a harsh response to any border violations by Syria.

Both sides have built up their military presence along their common border.

Turkey is sheltering more than 35,000 Syrian refugees who have fled the conflict, which has thus far claimed more than 16,500 lives according to estimates from the rights watchdog Syrian Observatory for Human Rights.