Turkish fighter jets shot down a Syrian warplane after it violated the country's airspace.

The move was likely to ramp up tensions between two countries already deeply at odds over Syria's civil war.

A spokesman for Syria's military confirmed the incident yesterday, denouncing it as a "blatant aggression".

The unnamed spokesman quoted on Syrian state TV said the plane was hit while pursuing gunmen near the border, and that the pilot safely ejected from the aircraft.

Syria's official SANA news agency quoted the pilot as saying that he was shot down while five miles inside Syrian airspace.

Turkey, a Nato member that once enjoyed good ties with Syria, has become one of the strongest critics of Syrian president Bashar Assad and is now one of the main backers of the three-year-old rebellion against him.

Hostilities have flared along the border on several occasions, although the exchanges of fire have generally been brief and very limited in scope.

Despite protestations from Syria, there was little indication either side wanted the confrontation to escalate.

The Turkish military said a Syrian MiG-23 entered Turkey's airspace near the Hatay border zone after ignoring four warnings to turn back.

One of two Turkish F-16s conducting a patrol in the area then fired a missile that struck the Syrian jet, which crashed 1,200 yards inside Syrian territory near the town of Kassab, the military said.

Turkish prime minister Recep Tayyip Erdogan, speaking at a rally ahead of local elections, congratulated the military, and said the strike should serve as a warning against further incursions.

"If you violate our border, our slap will be hard," he said.

The Lebanon-based Al-Mayadeen TV, which has a network of reporters around Syria, reported that the pilot of the downed warplane landed in the village of Bahluliya in Latakia province.

Syrian rebels launched an offensive in the Kassab area of Latakia near the Turkish border on Friday. The rugged hills near the frontier have been engulfed in heavy fighting since then.

The British-based Syrian Observatory for Human Rights reported clashes between troops and rebels led by fighters from the al Qaida-linked Nusra Front near Kassab.

It said that some of the shells fired by Syrian troops fell on the Turkish side of the border.

State TV reported late yesterday that the commander of the pro-government National Defence Forces Hilal Assad was killed in the fighting against opposition fighters in Kassab.

The commander was a member of President Bashar Assad's family but the TV did not say if they were close relatives.

This is not the first time that the Turkish military has downed a Syrian aircraft near the border.

In September, a Turkish fighter jet shot down a Syrian military helicopter after it entered Turkish airspace.

The helicopter strayed more than a mile into Turkish airspace, but crashed inside Syria after being hit by missiles fired from the jet, Turkish officials said at the time.