Syria rebels near the village of Jamla on the Golan Heights have captured a convoy of United Nations vehicles and kidnapped 21 Filipino UN employees, according to a video released by the rebels on Wednesday.

The kidnappers were negotiating with UN forces and demanding that the Syrian regime remove all its troops from the area adjoining the Syrian side of the border with Israel.

The video clip showed a number of gunmen standing alongside the UN vehicles, while their apparent leader announced his demands. Some of the United Nations employees can be seen inside the vehicles.

In a second video, the same rebel spokesman is seen accusing the UN, the Assad regime and Europe of “collaborating with Israel.” 

The kidnapping exemplifies the escalation in the activity of the increasingly emboldened rebel forces in the area.

On Tuesday, footage aired by Israel’s Channel 10 revealed that al-Qaeda operatives fighting the Syrian regime have been watching and studying IDF patrols along the border, only meters away on the other side of the fence.

In a number of videos uploaded to the Internet, the fighters can also be seen holding various munitions, including old antitank rockets and heavy machine guns.

Last month, UN staffer Carl Campeau went missing in the Syrian Golan Heights, sources familiar with the case told The Times of Israel.

Campeau, a Canadian legal adviser, was stationed at the United Nations Disengagement Observer Force base on the Syrian side of the demilitarized zone. Attempts by The Times of Israel to contact Campeau on his cellphone and at his office were unsuccessful.

Last week, The Times of Israel quoted a rebel activist reporting that Assad’s army had fled the Golan Heights area bordering Israel, and that rebel forces were in control there.

UN Secretary-General Ban Ki-moon has warned of escalating military activity along the Israeli-Syrian border as a result of the intensifying Syrian conflict, which has gone on for two years and cost more than 70,000 lives.

In December, Ban accused the Syrian government of serious violations of the 1974 separation agreement and called on both countries to halt firing across the cease-fire line. He also cited numerous clashes between Syrian security forces and opposition fighters in the disengagement zone.

In response, he said, UNDOF has adopted a number of security measures.

The Israel Defense Forces declined to comment.

The Associated Press contributed to this report.