BEIRUT (Reuters) - Insurgents attacked a Syrian government security building in the northern city of Aleppo on Wednesday, setting off a bomb and then launching a ground assault, and a monitoring group said dozens were killed on both sides.
The Syrian Observatory for Human Rights, which tracks the violence using sources on the ground, said initial reports suggested the insurgents had set off the bomb in a tunnel dug under or near the Air Force Intelligence building in Aleppo.
Rebel sources and a combatant fighting on the government's side confirmed that part of the building had been destroyed in the attack.
Rami Abdulrahman, who runs the Observatory, said the dead included members of the Syrian intelligence apparatus, pro-government fighters, and attackers he identified as members of a jihadist group.
Aleppo, around 50 km (30 miles) south of the border with Turkey
, is divided between government forces and insurgent groups fighting to topple President Bashar al-Assad in a four-year-old conflict.
A UN envoy is currently trying to broker a ceasefire between insurgent and government forces.