( CNN ) -- U.N. forces withdrew Monday from the Syrian-controlled side of the Golan Heights , the world body confirmed . The U.N. statement cited the `` exceptionally challenging environment '' posed by armed rebel groups advancing on peacekeeping positions its observer force has held for close to four decades . The confirmation comes hours after a journalist working for CNN saw dozens of peacekeeping vehicles crossing into territory controlled by Israel . The withdrawal comes a little more than two weeks after Islamic militant fighters took some peacekeepers hostage and besieged others . Al-Nusra Front freed 45 U.N. peacekeepers from Fiji in good condition last week , while forces from the Philippines escaped after exchanging fire with militant fighters , according to media reports . The incidents occurred after Syrian rebel fighters took control of the only border crossing between Israel and Syria in the Syrian town of Quneitra in late August . U.N. forces have been stationed in the Golan Heights since 1974 following negotiations between Israel and Syria to reduce tensions along their shared border after hostilities in 1973 . Israel has occupied a portion of the territory since seizing it during its 1967 war with Egypt , Jordan and Syria . The U.N. Disengagement Observer Force includes 1,250 troops from six countries . In addition to Fiji and the Philippines , India , Nepal , Ireland and the Netherlands have troops assigned to the force . Austrian troops who had been taking part in the forces in 2013 pulled out after fighting in the Syrian-controlled Golan Heights between rebels and Syrian government forces . Golan Heights : Making wine in the shadow of war . CNN 's Kareem Khadder and Ben Wedeman contributed to this report .
U.N. peacekeepers withdrawing from Syrian-controlled Golan Heights . The withdrawal follows the capture of some peacekeepers by Syrian rebels . The peacekeepers were eventually released ; others escaped a militant siege . U.N. peacekeepers have been in the region since 1974 .