Austrian troops in the UN monitoring force on the Golan Heights began withdrawing on Wednesday, days after Vienna decided to quit the mission over security concerns, an AFP correspondent said.
A group of around 70 soldiers entered the Israeli side of the strategic plateau through the Quneitra crossing, the only direct passage between Israel and Syria, he said.
The troops, the first wave of the 378-strong Austrian contingent which is due to be pulled out in stages, arrived in jeeps accompanied by armoured vehicles before crossing through Syrian and Israeli controls.
They briefly entered a UN base on the Israeli side of the line, but shortly afterwards set out for Ben Gurion international airport near Tel Aviv in a convoy of five coaches accompanied by six smaller vehicles.
Austria, which has been a cornerstone of UNDOF, the UN force monitoring a ceasefire between Syria and Israel since 1974, announced on Thursday that it would withdraw its peacekeepers because of deteriorating security on the Golan Heights.
Defence Minister Gerald Klug said the pullout of Austria's soldiers on the Golan would take between two and four weeks.
A top Israeli government official told AFP on Tuesday that several dozen Austrian troops had already left the mission's headquarters. Israeli public radio said they were administrative staff.
"But the majority of soldiers will remain in place until the UN has found a country that can send troops to replace the Austrian ones," said the Israeli official, who asked not to be named.
The UN is trying to persuade Austria to slow down its withdrawal from the force which, since March, has numbered just over 900 troops.
When completed, the Austrian pullout will leave the force with just 534 troops: 341 from the Philippines and 193 from India, UN officials say.
A year ago UNDOF had more than 1,100 troops. But Japan and Croatia have pulled out their men in recent months as battles between Syrian troops and the rebels spilled into the ceasefire zone.
Earlier this year, Israel has expressed concern that the UN force could pull out altogether after rebels snatched 21 peacekeepers from the demilitarised zone.
Israel fears that the departure of UNDOF troops could leave a vacuum in the ceasefire zone, leaving it open to infiltration by hardline militant groups such as Al-Qaeda.