An armed group detained 43 UN peacekeepers during fighting in Syria early Thursday and another 81 peacekeepers are trapped, the United Nations said.

The peacekeepers were detained on the Syrian side of the Golan Heights during a "period of increased fighting between armed elements and the Syrian Arab Armed Forces," the office of UN Secretary-General Ban Ki-moon said in a statement. It said another 81 peacekeepers are "currently being restricted to their positions in the vicinity of Ar Ruwayhinah and Burayqah."

The statement did not specify which armed group is holding the peacekeepers. Various Syrian rebel groups, including the al-Qaeda-linked Nusra Front, have been fighting the Syrian military near the Golan Heights. On Wednesday, opposition fighters captured a Golan Heights crossing point on the disputed border between Syria and Israel.

UN spokesman Stephane Dujarric said the 43 detained peacekeepers are from Fiji and are thought to be in the southern part of the area of separation. The 81 troops from the Philippines had their movements restricted.

SYRIA-CRISIS/BORDER-FIGHTING

A member of the UN Disengagement Observer Force (UNDOF) rides atop an armoured vehicle near the Quneitra border crossing on the Israeli-occupied Golan Heights Wednesday. (Ronen Zvulun/Reuters)

"The situation is extremely fluid. Obviously, we are very concerned," Dujarric said.

"We are dealing with non-state armed actors," he said. "The command and control of these groups is unclear. We're not in a position to confirm who is holding whom. Some groups self-identified as being affiliated with al-Nusra, however, we are unable to confirm it."

The statement said the United Nations "is making every effort to secure the release of the detained peacekeepers," who are part of UNDOF, the mission that has been monitoring a 1974 disengagement accord between Syria and Israel put in place after the 1973 Six Day War.

Philippines military spokesman Lt. Col. Ramon Zagala said in a statement later that Syrian rebels demanded that the Filipino troops surrender their firearms, but the soldiers refused.

"They did not surrender their firearms as they may in turn be held hostage themselves. This resulted in a stand-off which is still the prevailing situation at this time," Zagala said.

UNDOF peacekeepers detained in the past

Foreign Affairs Minister John Baird said "Canada strongly condemns the capture" of the UN forces, as well as the "forced restrictions of movement by armed opposition forces in the Golan Heights."

In a statement released Thursday afternoon, Baird said Canada calls on "all parties to respect the impartiality of UN peacekeepers and their freedom of movement, safety and security."

In response to a CBC News inquiry, the Department of National Defence said three Canadians who are part of UNDOF were not detained and are safe and accounted for. 

The Quneitra crossing on the Golan is a strategic plateau captured by Israel in a 1967 Middle East war. Syria and Israel technically remain at war and are separated by a narrow buffer zone known as the area of separation that was established under a 1973 ceasefire formalized in 1974.

The Security Council condemned the detention of the 43 peacekeepers and the restriction of movement of the other 81 and called for their immediate release. A rapidly drafted press statement blamed "Security Council-designated terrorist groups" and "members of non-state armed groups."

In June, the UN Security Council strongly condemned the intense fighting between Syrian government and opposition fighters in the Golan Heights and demanded an end to all military activity in the area. Syrian mortars overshooting their target have repeatedly hit the Israeli-controlled Golan, and UN peacekeepers have been abducted.

Thursday's statement noted that UNDOF peacekeepers who were detained by armed forces in March and May were later safely released.

As of July, UNDOF has 1,223 troops from six countries: Fiji, India, Ireland, Nepal, Netherlands and the Philippines.

But the Philippine government last week said it would bring home its 331 peacekeeping forces from the Golan Heights after their tour of duty ends in October, amid the deteriorating security in the region.

In June 2013, Austria said it was withdrawing its 377 UN peacekeepers from the Golan Heights. Croatia also withdrew in 2013 amid fears its troops would be targeted.

With files from Julie Van Dusen and Reuters