Armed fighters in the Golan Heights on Tuesday abducted four Filipino UN peacekeepers, the second seizure in two months linked to Syria's civil war, the United Nations said.

A Syrian rebel group claimed responsibility for the abductions. The four were "detained today by an unidentified armed group while they were patrolling" near Al Jamlah in the ceasefire zone between Israel and Syria, said a UN peacekeeping spokeswoman Josephine Guerrero.

"The four are from the Philippine battalion. Efforts are underway to secure their release," Guerrero added.

Twenty-one Filipino peacekeepers were seized in the same area by Syrian rebels in March. UN Secretary General Ban Ki-moon strongly condemned the latest attack on peacekeepers in the tense ceasefire zone. UN officials, speaking on condition of anonymity, said there has been mounting military activity by Syrian government and opposition forces in recent days in the zone patrolled by the UN Disengagement Observer Force (UNDOF).

In a Facebook posting, 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 rebel group also staged the abduction in March. The Yarmuk Martyrs Brigade said it staged "an operation to secure and protect United Nations forces in Wadi Yarmuk in the area between Syria and the occupied Golan Heights."

Ban "strongly condemns the detention of four UNDOF peacekeepers by armed elements" and "calls for their immediate release," said the UN spokesman Martin Nesirky. "The secretary general calls on all parties to respect UNDOF's freedom of movement and safety and security," he added.