QUNEITRA CROSSING, Golan Heights, June 12, 2013 (AFP) - 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 photographer said.

A group of 20 soldiers entered the Israeli side of the strategic plateau through the Quneitra Crossing, the only direct passage between Israel and Syria, the photographer said.

The troops arrived in jeeps accompanied by armoured vehicles before crossing through Syrian and Israeli controls.

About 50 other soldiers of the 378-strong Austrian contingent were to be withdrawn during the day, sources on the ground said.

Austria, which has been a cornerstone of the United Nations 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.

Japan and Croatia have also withdrawn in recent months as battles between Syrian government and opposition forces spill into the ceasefire zone.