A Syrian intelligence officer died when rebels blew up a security headquarter near the Syrian-Israeli border, activists said Friday.
The Syrian Observatory for Human Rights said eight security personnel were also killed in the blast.
"The headquarters in Sasa area witnessed heavy clashes with government militia manning the facility, then it was blown up by members of the al-Nousra Front," Damascus-based Haytham al-Abdllah told dpa.
Brigadier Adnan Ibrahim was killed along with several of his troops in the operation, he added.
Al-Nousra Front, a hardline group fighting President Bashar al-Assad's forces along with the Free Syrian Army rebels, released prisoners before the explosion late Thursday, al-Abdllah said.
The group is classified as a terrorist organization by the United States.
The state-run news agency SANA confirmed that an explosion had taken place in Sasa, but did not give details.
Sasa is located in the southwestern province of Quneitra, in the Syrian-controlled part of the Golan Heights. Israel captured around two-thirds of the Golan Heights during the six day Arab-Israel war in 1967 and annexed it in 1981.
Israel has twice last year fired across the ceasefire line, in response to stray fire from Syrian troops fighting rebels inside the zone.