JERUSALEM (Reuters) - Israel voiced confidence on Thursday that the United Nations could secure the release of U.N. peacekeepers seized by Syrian rebels near the Golan Heights, signaling it would not intervene in the crisis.

"Restricting the movement of troops in an international force is a significant event," Amos Gilad, a senior Defense Ministry official, told Israel Radio. "The United Nations ... can be trusted to persuade them (the rebels) ultimately to free them."

Gilad said the rebels, seeking foreign support, had no interest "in getting into a confrontation with the international community".

Israel's military, he said, was taking a "low profile" but following events in Syria closely.

Israel captured the Golan Heights in a 1967 war, and mortar fire from Syria's civil war has occasionally spilled over into the strategic plateau.

Peacekeepers of the U.N. Disengagement Force (UNDOF) mission have been monitoring a ceasefire line between Syria and the Israeli-occupied heights for nearly four decades.

Rebels holding the 21 peacekeepers near the Golan Heights said Syrian government forces must leave the area before they free them, an activist in touch with the fighters said.

(Reporting by Jeffrey Heller, Editing by Ari Rabiniovitch)