Activists say Syrian rebels are clashing with government troops in the Golan Heights near the border with Israel, where al-Qaida-linked insurgents abducted U.N. peacekeepers last week.

The Britain-based Syrian Observatory for Human Rights says the fighting on Monday was focused around the town of Hamidiyeh in Quneitra province.

The Observatory says there were casualties on both side, but did not have exact figures.

Heavy fighting has raged in the area since Syrian rebels captured a border crossing near the abandoned town of Quneitra on Wednesday.

A day later, fighters from al-Qaida's Syria branch, the Nusra Front, abducted 45 Fijian peacekeepers who serve in the U.N. mission that monitors the buffer zone between Israel and Syria.

The United Nations says it is seeking the Fijians' immediate an unconditional release.