MANILA (AFP) - The Philippines threatened on Thursday to withdraw its troops from the United Nation's peacekeeping force on the Golan Heights unless they receive anti-tank and anti-aircraft weapons, and are protected against chemical arms.

President Benigno Aquino said the UN Disengagement Observer Force (UNDOF), now made up of just over 500 Filipino and Indian troops, needed revised rules of engagement as Syria's civil war heats up.

The Philippines pledged on Wednesday to keep its troops in the volatile strip of land between Syria and Israel until at least Aug 3, but said its continued presence would depend on the UN beefing up security.

"We're trying to identify all the potential threats. Were they to be confronted with tanks, do we have the capability? We (should) get anti-armour," Mr Aquino told reporters. "Against aircraft that may threaten their position, we are trying to get them anti-aircraft (weapons)."

Mr Aquino also referred to "allegations that chemical weapons are now being employed in the Syrian civil war" as he pressed for the UN to do more.

The United States said last week it had proof that Syrian government forces had carried out deadly chemical attacks against rebels, and that Washington would be providing military support to the opposition. The Syrian regime and Russia dispute the allegation about chemical weapons.

Mr Aquino said if his government's demands were met, "the mission will become tenable, and we would then be able to stay there to help the entire world". "But if our requests are not granted, I will not risk keeping our troops there without the resources required to carry out their mission."

British Ambassador Mark Lyall Grant, the UN Security Council president for June, said on Tuesday that UNDOF would get "some heavier weapons", extra body armour and see observation posts reinforced.

However, Philippine military spokesman Domingo Tutaan told AFP he was unaware of whether UNDOF now had that equipment as demanded by Mr Aquino.

The Philippines had warned in recent weeks that it was considering pulling out its 341 soldiers from the force after 25 of them were kidnapped by Syrian rebels in two separate incidents this year. They were released unharmed but the abductions, as well as the wounding of a Filipino soldier at an UNDOF outpost, heightened concerns about the peacekeepers' safety.

UN peacekeepers have been monitoring a ceasefire between Syria and Israel in the Golan Heights since 1974, but violence has escalated as the Syrian civil war spills over into the area.

Austria began pulling out its 370 peacekeepers last week because of the security concerns, following similar moves by Japan and Croatia.

However, UN diplomats said on Tuesday that Fiji had offered to send 500 troops.