Syrian officials said the defences forced the jets to drop ammunition over deserted areas and turn back, according to the official news agency, Sana.

Israel's military said it would not comment on the reports.

Israel and Syria remain technically at war and tensions between them have been rising in recent months.

The Syrian government has insisted that peace talks can be resumed only on the basis of Israel returning the Golan Heights, which it seized in 1967.

Israeli authorities, for their part, have demanded that Syria abandon its support for Palestinian and Lebanese militant groups before talks can begin.

The last peace talks between the two countries broke down in 2000.

'Enemy aircraft'

A Syrian military spokesman said the Israeli warplanes had flown into Syrian airspace at around 0100 local time on Thursday morning, Sana reported.

"The Israeli enemy aircraft infiltrated into the Arab Syrian territory through the northern border, coming from the Mediterranean heading toward the eastern region, breaking the sound barrier," he said.

They were then engaged by Syrian air defence forces in the Tall al-Abyad, an area 160km (100 miles) north of Raqqa and near the border with Turkey, witnesses said.

Israel in fact does not want peace - it cannot survive without aggression, treachery and military messages

Mohsen Bilal

Syrian Information Minister

New twist to Israel tensions

"Air defence units confronted them and forced them to leave after they dropped some ammunition in deserted areas without causing any human or material damage," the spokesman said.

Pilots sometimes jettison ammunition or extra fuel to make their aircraft lighter and easier to manoeuvre.

Syria's Information Minister, Mohsen Bilal, told al-Jazeera TV that his government was "seriously studying the nature of the response".

"Israel in fact does not want peace," he said. "It cannot survive without aggression, treachery and military messages."

Tensions

Officials in Damascus said Syrian forces last fired at Israeli warplanes in June 2006, when they flew over the summer residence of the Syrian president in Lattakia, while he was inside.

The Syrian armed forces have a wide array of anti-aircraft weapons

Over the past few months, the leaders of both countries have both stressed that they do not want war.

But both sides have also been preparing for possible conflict.

In June, Israeli Prime Minister Ehud Olmert insisted his country did not want war with Syria, and that he had communicated this to Damascus through diplomatic channels.

He also repeated his warning that a "miscalculation" could spark hostilities between the two.

Mr Olmert's statement came after the Israeli military staged major exercises in the Golan Heights. Syria is also reported to have recently built up its armaments along the border.