Syrian forces fought gunmen in battles that left more than 120 members of the security forces dead, state television said in the first report of large-scale armed clashes in the revolt against President Bashar al-Assad.

The television said on June 5 armed groups set government buildings ablaze in the northwestern town of Jisr al-Shughour, stole five tons of dynamite and were firing at civilians and security forces with machineguns and rocket-propelled grenades.

"The security forces have managed to end a blockade of one of the neighborhoods that was seized by the gunmen for awhile and are now battling them to end the blockade of the other neighborhoods," the television said.

"The gunmen mutilated some of the bodies and threw some into the river. The people in Jisr al-Shughour are urging the army to intervene speedily," it said.

Opposition activists earlier said a security operation had been under way in the town since Saturday in which they said at least 37 residents and 10 police had been killed.

But it was impossible to verify the conflicting accounts of the violence from activists and officials as authorities have prevented most international media from operating in Syria, Reuters reported.

Interior Minister Mohammad Ibrahim al-Shaar said authorities would respond firmly to armed attacks and Information Minister Adnan Mahmoud said the army, which has so far stayed out of the town, "will carry out their national duty to restore security."

Rights groups say 1,000 civilians have been killed in the protests which have swept from the southern city of Deraa to the Mediterranean coast and eastern Kurdish regions.