The United Nations Security Council condemned on Wednesday evening the seizure of 20 UN peacekeepers by Syrian rebels and demanded their immediate release.

“The members of the Security Council strongly condemned the detention of a group of more than 20 peacekeepers … by armed elements of the Syrian opposition,” Russian UN Ambassador Vitaly Churkin, this month’s president of the 15-nation council, told reporters.

UN Secretary-General Ban Ki-moon also condemned the kidnapping and called for their release.

“The Secretary-General reminds all actors in Syria that UNDOF is mandated to monitor the Disengagement of Forces Agreement between Israel and Syria. UNDOF’s freedom of movement and safety and security must be respected by all parties,” said a statement released by Ban’s spokesman, Martin Nesirky.

Earlier Wednesday the international body confirmed that about 20 UN observers had been detained by approximately 30 armed rebels in the Golan Heights on the Syria-Israel border.

The confirmation came in response to a video posted on the Internet that portrayed men claiming to be Syrian rebels standing next to vehicles marked with the letters “UN”.

The rebels are demanding that President Bashar Al-Assad’s forces withdraw from the outskirts of the village of Jamla in exchange for the release of the peacekeepers.

The incident comes a week after the United Nations confirmed that a member of the UN peacekeeping force charged with monitoring the ceasefire between Israeli and Syrian troops on the Golan Heights is missing.

UN deputy spokesman Eduardo del Buey would not say whether the missing person was a military or civilian member of the international or local staff.

UNDOF was established in 1974 following the 1973 Yom Kippur war to monitor the disengagement of Israeli and Syrian forces and maintain the ceasefire in the area.

In November, two Austrian soldiers from the force were wounded in Syria and were taken for treatment at the Rambam Hospital in Haifa.

The two soldiers were shot and wounded while their convoy was travelling to the Damascus airport.

Meanwhile, a video published Tuesday showed Al Qaeda terrorists along Israel’s northern border from the Golan Heights, tracking IDF soldiers from the Syrian side of the fence.

The operatives, who are fighting on the side of the opposition forces attempting to oust Syrian President Bashar al-Assad, are members of a 13-faction radical Islamic coalition, the Islamic Front for the Liberation of Syria that has declared itself completely separate from the mainstream opposition sector. Most of the group’s members are linked to the international Al Qaeda terrorist organization.