AN armed group has abducted four UN peacekeepers from the Philippines in the Golan Heights, which has been hit by mounting spillover from the Syrian civil war, the United Nations says.

The four were patrolling near the Al Jamlah locality in the ceasefire zone between Israel and Syria where 21 Filipino peacekeepers were seized by Syrian rebels in March, said a UN peacekeeping spokeswoman, Josephine Guerrero.

"An unknown armed group" took the men, Guerrero told AFP. "Efforts are underway to secure their release."

In a posting on their Facebook page, the "Yarmuk Martyrs Brigade" rebel group said they had taken the four peacekeepers for their own safety because of fierce fighting in the area.

"The leadership of the Yarmuk Martyrs Brigade announces... an operation to secure and protect United Nations forces in Wadi Yarmuk in the area between Syria and the occupied Golan Heights," the group said.

The posting showed a photograph of four men in blue flak jackets, with three of them marked "UN" and "Philippines."

The statement said shelling by regime troops and fighting in the area "seriously threatened the safety" of the peacekeepers and had prompted the fighters to "intervene and work to get them out."

The Syrian Observatory for Human Rights watchdog confirmed there was heavy fighting underway in the area.

The UN Disengagement Observer Force (UNDOF), which has been in the Golan Heights since 1974, has about 1,000 troops and civilian staff.

The 917 troops from Austria, India, the Philippines, Morocco and Moldova carry only very light arms.