BEIRUT: A car bomb blast shook the Damascus region early Tuesday, a day after nearly 250 people died in fighting and bombings in Syria's worst violence since last month's failed ceasefire bid, a watchdog said.

The car bomb exploded in the city of Mudamiya near the capital, causing injuries and significant damage, the Syrian Observatory for Human Rights (SOHR) said.

Fighting and military shelling also hit the area, said the Britain-based Observatory, which relies on a countrywide network of activists and medics in civilian and military hospitals.

Air strikes also hit targets in Douma, 13 kilometres northeast of the capital, dropping two bombs on buildings in the heart of the city, it said. Other air raids struck hit the northern town of Al-Bab and in the central Homs province.

The Observatory said the army was shelling areas in the western Latakia region, in Homs and in Quneitra, near the Golan Heights, where the Israeli army said Monday that gunfire from the Syrian side had hit an Israeli military vehicle.

Fighting was also raging in northern commercial hub Aleppo, where two rebels were killed, and in the eastern Deir Ezzor province, it said.

The Observatory said 247 people were killed on Monday, including 93 soldiers, 86 civilians and 68 rebel fighters. It was the deadliest day in Syria since an attempt to impose a ceasefire for the October 26-29 Eidul Azha Muslim holiday collapsed.

In one of the most devastating attacks on President Bashar al-Assad's forces since the start of the Syrian uprising, a rebel car bomb killed 50 pro-regime fighters at a military post in the central province of Hama on Monday.

Another car bomb attack struck Monday in the west Damascus district of Mazzeh, home to many embassies and state security offices, killing 13 civilians, the Observatory said.

An air strike in the Idlib province town of Kafr Nabal also killed 22 civilians on Monday, the Observatory said, with a video posted online by activists showing rescuers carrying blood-soaked bodies amid burning cars and uprooted trees.

The Observatory says more than 36,000 people have died since the uprising against Assad's rule broke out, first as a protest movement inspired by the Arab Spring and then as an armed rebellion.