MAJDAL SHAMS, Golan Heights, June 5 (Allyn Fisher-Ilan/Reuters) - Israeli troops opened fire on Sunday at Palestinian protesters in Syria who rushed towards a border fence and Syrian state television said four demonstrators were killed.

Anyone who tries to cross the border will be killed, Israeli soldiers shouted at the crowd of several hundred through loudspeakers on the occupied Golan Heights.

Sunday marked the 44th anniversary of the 1967 Middle East war and Israel had been on high alert for a feared repetition of the storming last month by thousands of Palestinian protesters of Israel's frontiers with Syria and Lebanon.

Thirteen people were killed in those demonstrations marking the Naqba, or what Palestinians term the catastrophe of Israel's founding in 1948.

Rallying again to calls on Facebook to march to Israel, Palestinians in Syria descended from a hilltop overlooking the Druze village of Majdal Shams and reached the disputed border, that before last month had been largely tranquil for decades.

Syrian TV said four protesters were killed by Israeli gunfire and 13 injured. Israel's chief military spokesman, Brigadier-General Yoav Mordechai, said troops had opened fire but that he could not confirm any casualties.

He told Israeli Army Radio that if the Syrian state television death toll was correct and Israeli soldiers had succeeded in stopping protesters from breaching the fence, then, I think that's a measured, focused and proper response.

A Reuters correspondent at the scene saw at least seven demonstrators carried away on stretchers by the crowd but no sign of any holes in the barbed wire barrier.

FLAG PLANTED

Protesters managed, however, to plant a Palestinian flag on the fence on the rocky plateau, which Israel captured along with the West Bank and Gaza Strip in the 1967 conflict.

Hours before the violence flared, Prime Minister Benjamin Netanyahu said he had ordered Israeli forces to act with restraint, but with determination, to prevent any border breach.

To my regret, today there are extremists around us trying to breach our borders, and threaten our towns and citizens. We will not allow this, Netanyahu told his cabinet.

Facing demonstrators waving Palestinian flags, Israeli marksmen crouched in positions along the Syrian frontier. A spotter next to the riflemen peered at the protesters through
long-range binoculars.

At one point, protesters in a trench turned eastward toward Mecca and knelt in prayer. Other demonstrators gave the V-for-Victory sign.

There were no reports of incidents along the Lebanese border. In the occupied West Bank, about 100 Palestinian protesters marched to an Israeli military checkpoint, where soldiers fired teargas and the crowd fled.

A Palestinian medic said 10 Palestinians were wounded by rubber bullets in ensuing clashes between stone-throwing youths and Israeli soldiers.

Israeli officials have suggested that Syrian President Bashar al-Assad has given the green light for the Golan protests to try to divert international attention from his bloody quashing of the popular revolt against his authoritarian rule.

The border protests by unarmed demonstrators have raised Israeli concerns that Palestinians, inspired by popular revolts in the Arab world, have adopted a new tactic calculated to draw a violent response and boost world sympathy for their cause.

Palestinians walked out of U.S.-sponsored peace talks shortly after they began last September, in a dispute with Netanyahu over building in Jewish settlements in the West Bank.

(Additional reporting by Laila Bassam in Beirut; Writing by Jeffrey Heller, Editing by Crispian Balmer)