Austrian troops, who form the biggest contingent of UN peacekeepers on the Golan Heights, began to withdraw on Wednesday over security concerns after battles between Syrian soldiers and rebels spilled into the cease-fire zone.

The pullout comes despite UN appeals for more time to find a replacement for the departing soldiers, whose absence Israel fears will leave the plateau open to infiltration by Islamic militants.

It represents yet another headache for the international community as it struggles to find a political solution to the Syrian civil war, which has already killed an estimated 94,000 people, uprooted millions and occasionally spread into neighboring countries.

Seventy of Austria's 378-strong contingent in the UN Disengagement Observer Force (UNDOF) entered the Israeli side of the Golan through the Quneitra crossing, the only direct passage between Syria and Israel, an AFP correspondent said.

They arrived in jeeps accompanied by armored vehicles before going through Syrian and Israeli security checks and setting off for Ben Gurion international airport near Tel Aviv.

Austria has been a cornerstone of the UNDOF, which has monitored the armistice line between Syria and Israel since 1974, and said it was pulling out because of deteriorating security.

The withdrawal is expected to take two to four weeks, and will leave UNDOF with just 534 troops, 341 from the Philippines and 193 from India.

In the latest violence in Syria, a Syrian helicopter fired three missiles Wednesday on a Lebanese border town whose majority Sunni residents back the revolt against President Bashar al-Assad, a security official said, adding several people were wounded.

Lebanon's army said it will immediately respond to any further cross-border attacks by the Syrian military

Also on Wednesday the army fired a barrage of shells as it advanced on Wadi Sayeh, a rebel stronghold of the central city of Homs, said the Syrian Observatory for Human Rights.

At least 257 people were reported to have been killed across the country on Tuesday, including at least 60 Shiites slain in clashes with rebels in the east.

In the past week, government troops and thousands of fighters from the powerful Lebanese Shiite movement Hezbollah overran rebels in central Syria, including in the strategic town of Qusayr. Syrian troops are now focusing their attention on the strategic northern city of Aleppo as they continue to gain ground against the rebels.

France urged the international community to stop the Assad regime.

"We need to re-balance things because over the past few weeks the troops of Bashar al-Assad and especially Hezbollah and the Iranians, along with Russian arms, have gained considerable ground," said Foreign Minister Laurent Fabius.

But he did not expand on how Syrian troops, buoyed by military support from its Shiite allies Hezbollah and Iran, should be stopped.

AFP