* Israel and Syria help get troops back to base
* Islamist militants battle forces loyal to Assad on Golan (Adds Israeli prime minister's comments, details, background)
By Avi Ohayon
EIN ZIVAN, Golan Heights, Aug 30 (Reuters) - Thirty-two U.N. peacekeepers were rescued on Saturday from Islamist militants who fired at their post on the Syrian side of the Golan Heights and trapped them for two days, the United Nations said.
Another group of U.N. soldiers - also from the Philippines - remained trapped by the Islamists, who surrounded their positions on Thursday, and a gunbattle was continuing, the U.N. press office said. There was no immediate word on whether there were casualties.
The troops are part of UNDOF, a U.N. force that has monitored the disengagement zone between Israel and Syria since 1974, following the 1973 Arab-Israeli war.
A Reuters cameraman spotted 11 U.N. armoured vehicles returning to their base in Israeli-controlled territory about 12 hours after the peacekeepers came under fire at around 6 a.m. (0400 GMT) on Saturday.
"All 32 Filipino personnel from this position have been extricated and are now safe," the United Nations press office said in a statement issued in New York.
The remaining troops, at a separate border post, were still under mortar and heavy machinegun fire, the statement said.
"The U.N. peacekeepers returned fire and prevented the attackers from entering the position," it said. Officials in the Philippines have said there were a total of 72 soldiers trapped in the area.
Another 44 UNDOF peacekeepers, from Fiji, were detained by militants 8 km (5 miles) away from the Philippine troops on Thursday and remain missing.
A U.N. official said a number of UNDOF contingents participated in the action on Saturday, assisted by Israeli and Syrian forces. It was unclear what form that assistance took.
UNDOF has 1,223 peacekeepers in the zone from six countries - Fiji, India, Ireland, Nepal, Netherlands and the Philippines.
The United Nations said this week the Philippines had decided to pull out of UNDOF and from a U.N. force in Liberia, which is struggling with an outbreak of the deadly Ebola virus.
Blue-helmeted U.N. troops were seized by militants in March and May 2013. In both cases they were released safely.
Austria, Japan and Croatia have all pulled their troops out of UNDOF due to the deteriorating security situation and spillover from the Syrian war.
The Golan is a strategic plateau captured by Israel in the 1967 Middle East War, and Syria and Israel technically remain at war. UNDOF monitors the area of separation, a narrow strip of land running about 70 km (45 miles) from Mount Hermon on the Lebanese border to the Yarmouk River frontier with Jordan.
Rebels of the Islamist Nusra Front, a group linked to al-Qaeda, have been battling the Syrian army in the area and have wrested control of the border crossing at Quneitra, which is operated by the U.N.
Asked how Israel intends to meet the new challenge in the Golan area, Prime Minister Benjamin Netanyahu told Channel 10 television in an interview recorded on Friday and aired on Saturday Israel was prepared to face the threats.
"We have already taken steps. We did not wait, we built and renovated the security fence. Al Nusra has been present there for about the past five months. We are prepared for various possibilities," he said.
He added that the current situation was a manifestation of the volatility of the region.
"We live in a tough Middle East, in a tough area, and compared with other countries, we are taking care of our security and economy better than everyone. But we face challenges on a number of fronts," he said. (Additional reporting by Louis Charbonneau at the United Nations in New York and Rosemarie Francisco and Manuel Mogato in Manila; Writing by Ori Lewis; Editing by Andrew Roche)