AMMAN: Heavy fighting erupted in Damascus on Wednesday as rebels launched an offensive against President Bashar al-Assad's forces, breaking a lull in the conflict, opposition activists said.

Assad's forces also came under attack in the east of the country, where a suicide car bomb struck a military intelligence compound in the city of Palmyra, causing dozens of casualties, they said.

Authorities in Damascus closed the main Abbasid Square and the Fares al-Khoury thoroughfare as fighters attacked roadblocks and fortifications with rocket-propelled grenades and mortars.

“The areas of Jobar, Zamalka, al-Zablatani and parts of Qaboun and the ring road have become a battleground,” activist Fida Mohammad said from the district of Qaboun.

Another activist said an army tank stationed at the main al-Kabbas roadblock on the ring road had been destroyed. Residents reported explosions across the east and north of the capital.

In Jobar, a working-class Sunni Muslim area adjacent to Abbasid Square, mosque speakers chanted “God is Greatest” in support of opposition fighters who attacked roadblocks in the neighbourhood, activists said.

They said tanks stationed on the edge of the central district of Midan, just outside the walls of Old Damascus, shelled southern districts of the city.

Syrian state television said: “Our noble army is continuing its operations against the terrorists in Irbeen, Zamalka and Harasta and Sbeineg, destroying the criminal lairs.”

Assad's symbols of power came under attack in Palmyra, 220 km (140 miles) northeast of Damascus, on the main road to the oil-producing east of the country.