Rebels have gained control of the Syrian side of the Quneitra border crossing, between the Israeli-controlled and the Syrian-controlled part of the Golan Heights, dpa reported according to Israeli media.
The Syrian rebels are now closer to Israel than ever, the reports said.
An Israeli military spokeswoman in Tel Aviv could not confirm that report or ones of an Israeli military build-up in the area. But she confirmed that Israel declared its side of the border a "closed military zone," instructing farmers and civilians to stay away from the area.
A UN soldier with the force observing the border has reportedly been injured on the Syrian side, but the spokeswoman was also unable to confirm this.