UN Secretary-General Ban Ki-moon on Sunday voiced concerns at reported clashes between the armed opposition and Syrian security forces.

Ban urged Syria and Israel to "uphold the Disengagement Agreement" in a statement issued here by his spokesman after the clashes broke out in a slice of the Syrian territory patrolled by the UN peacekeepers to maintain a cease-fire with Israel.

"The secretary-general is concerned by reports of clashes between the armed opposition and Syrian security forces in the UN Disengagement Observer Force (UNDOF)-supervised area of separation, in which Syrian small arms fire and one artillery round reportedly landed in the Israeli-occupied Golan today and prompted a response by Israel," the statement said.

"No injuries to civilians or UN personnel in either instance were reported," the statement said.

Violence has become rampant in several parts of Syria, giving no sign of backing down amid high frustration among the people who grew more tensed with the daily grind of chaos.

The UNDOF was established by United Nations Security Council Resolution 350 on May 31, 1974 to implement Resolution 338, adopted by the Security Council in 1973, which called for an immediate cease-fire and implementation of United Nations Security Council Resolution 242.

Resolution 242 was passed on the same day the Agreement on Disengagement was signed between Israeli and Syrian forces on the Golan Heights, finally establishing a cease-fire to end the 1973 Yom Kippur War.

The UN peacekeeping force has since performed its functions with the full cooperation of both sides. The mandate of UNDOF has been renewed every six months since 1974.

"The secretary-general is deeply concerned by the potential for escalation," the statement said.

"He calls for the utmost restraint and urges Syria and Israel to uphold the Disengagement Agreement, respect their mutual obligations, and halt firing of any kind across the cease-fire line," said the statement.