UNITED NATIONS (Reuters) - The United Nations said about 20 peacekeepers had been detained by around 30 armed fighters in the Golan Heights on the border between Syria and Israel on Wednesday and that it has sent a team to resolve the situation.

The United Nations confirmation came in response to YouTube videos purporting to show Syrian rebels with the seized convoy. Syria's two-year civil war, which has killed more than 70,000 people, has been spilling over into the Golan Heights area.

"The U.N. observers were on a regular supply mission and were stopped near Observation Post 58, which had sustained damage and was evacuated this past weekend following heavy combat in close proximity, at Al Jamlah," the United Nations said in a statement issued in New York.

Israel captured the Golan Heights from Syria in a 1967 war. Syrian troops are not allowed in the area of separation under a 1973 ceasefire formalized in 1974. Israel and Syria are still technically at war. The area is patrolled by U.N. peacekeepers.

Israel warned the U.N. Security Council on Monday that it could not be expected to "stand idle" as Syria's civil war spills over its border, while Russia's U.N. envoy Vitaly Churkin accused armed groups of undermining security between the states by fighting in the Golan Heights.

(Reporting by Michelle Nichols; Editing by Doina Chiacu and Cynthia Osterman)