* Israel and Syria help get troops back to base, U.N. says
* Islamists reinforce siege of second group of peacekeepers (Adds quote from U.N. official in paragraph 2)
By Louis Charbonneau and Avi Ohayon
UNITED NATIONS/EIN ZIVAN, Golan Heights, Aug 30 (Reuters) - T hirty-two Philippine U.N. peacekeepers were rescued on Saturday from Islamists who fired at their post on the Syrian side of the Golan Heights and trapped them for two days, U.N. officials said, while militants reinforced their siege of another group of 40.
"The situation at Position 68 is calm but tense, as more than 200 militants have assembled around it in the last few hours," a U.N. official said, referring to the place where the 40 Philippine peacekeepers were trapped.
A U.N. diplomatic source said earlier: "As we speak more rebels in more than 20 vehicles are approaching and reinforcing the siege around Position 68."
The rebels began to arrive at 11 p.m. local time (2000 GMT), added the source, who spoke on condition of anonymity.
The peacekeeping 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.
Earlier on Saturday, 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. (0300 GMT).
"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 U.N. peacekeepers returned fire and prevented the attackers from entering the position," it said. Officials in the Philippines said a total of 72 soldiers had been trapped.
Separately, 44 UNDOF peacekeepers from Fiji were detained by militants 8 km (5 miles) away from the Philippine troops on Thursday and remain missing.
REBELS SAY FIJIANS IN GOOD HEALTH
A commander with the Islamist Nusra Front, a group linked to al Qaeda, told Reuters the Fijian peacekeepers had been detained because UNDOF was aiding the government of President Bashar al-Assad and had ignored the suffering of the Syrian people.
UNDOF has been deployed "since 1974 to ensure the safety and protection of the borders with (Israel), the usurper of the lands of the Muslims, at the same time it completely ignored the daily shedding of the Muslims' blood on the other side of the border," part of a Nusra Twitter message said.
It added that the men were being treated well and were in good health.
A U.N. official said a number of UNDOF contingents participated in the rescue 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, the 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 on the Golan Heights 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 Nusra Front have been battling the Syrian army in the area and have wrested control of the border crossing at Quneitra, which is operated by the United Nations.
Asked how Israel intends to meet the new challenge in the Golan area, Prime Minister Benjamin Netanyahu said in an interview recorded on Friday and aired on Saturday that 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 told Channel 10 television.
"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," Netanyahu said. (Additional reporting by Mariam Karouny in Beirut, Jeffrey Heller in Jerusalem and Rosemarie Francisco and Manuel Mogato in Manila; Writing by Ori Lewis; Editing by Andrew Roche and Mohammad Zargham)