Syrian warplanes pounded opposition strongholds around Damascus and in the north as President Bashar Assad's forces intensified airstrikes following the failure of a UN-backed cease-fire, activists said.

The Britain-based Syrian Observatory for Human Rights, which gathers reports from a network of activists on the ground, said government jets carried out five strikes in the eastern Ghouta district, a rebel stronghold close to the capital.

Three airstrikes also hit the rebel-held city of Maaret al-Numan, which straddles a key supply route from Damascus to Aleppo and has become a main front in the civil war.

No casualties were reported in Wednesday's strikes, the Observatory said.

However, at least 185 people were killed nationwide in airstrikes and artillery shelling the day before, pushing the total death toll since the conflict began in March 2011 to over 36,000, according to the Observatory's president Rami Abdul-Rahman. At least 47 soldiers were also killed Tuesday, the Observatory said.

Syria's crisis began as a peaceful uprising against Assad's regime inspired by the Arab Spring, but it quickly morphed into a civil war.

The international community remains at a loss about how to stop the war. A temporary truce timed to coincide with a major Muslim holiday last week failed to take hold as more than 500 people were killed in fighting during the four day period.

The US and other Western and Arab nations have called on Assad to step down, while Russia, China and Iran continue to back him.

The UN-Arab League envoy to Syria, Lakhdar Brahimi, met yesterday with China's Foreign Minister Yang Jiechi to solicit Beijing's support for international efforts to stop the bloodshed.

Brahimi said he hoped "China can play an active role in solving the events in Syria."

Yang said that China is willing to work with the international community to make continuous efforts to achieve a "fair, peaceful and appropriate" resolution, according to Xinhua.

In the past weeks, the regime has intensified airstrikes on rebel positions and strongholds, particularly Maaret al-Numan, a city of 180,000 people that fell to rebel forces on Oct. 10.

A former resident of the city said more than 70 homes have been levelled as a result of air bombardments this week alone.

"The Syrian air force doesn't leave the skies. When the warplane goes, the helicopter comes," the resident who identified himself as Ahmad said in a phone interview overnight (NZ time). He spoke from a nearby village and would only give his first name for fear of reprisals from the regime.

Most of the city's inhabitants have fled due to heavy fighting, Ahmad said.

"Everyone has fled, you can't live here anymore," Ahmad said, adding that rebel groups, including the al-Qaida inspired Jabhat al-Nusra, had flocked to the area to defend it.

The inability to sustain even a limited truce has raised fears of a prolonged conflict in Syria that could drag in its neighbours such as Turkey, Lebanon and Jordan.

Turkey's Foreign Minister Ahmet Davutoglu on Tuesday expressed "great sadness" that the holiday cease-fire had failed and said his government was done talking to Assad's regime.

That prompted angry comments from the Syrian government against its former ally.

Syria's Foreign Ministry spokesman, Jihad Makdessi, accused Turkey of having "destructive policies" against Damascus and claimed Davutoglu, was "targeting the security and stability" of Syria.

The spokesman insisted it was the unwillingness of Turkey and Gulf states to cease supporting the rebels that doomed the truce, the state-run SANA news agency reported late Tuesday.

Damascus views the rebels as terrorists and accuses them of being foot soldiers in a foreign plot to destroy Syria.

Also Wednesday, SANA said a bomb hidden in a garbage bag exploded in an area near Damascus that is home to a Shiite Muslim shrine, killing six people and wounding 13. The Observatory said at least eight people were killed.

The blast occurred in a suburb of the capital housing the golden-domed shrine of Sayeda Zeinab, the Prophet Muhammad's granddaughter, which is popular with Iranian worshippers and tourists.

The UN refugee agency, meanwhile, said it delivered badly needed humanitarian aid to internally displaced Syrians in the northern cities of Aleppo and Idlib, as well as in Homs in the center of the country and Hassakeh and Raqqa in the northeast. Speaking in Jordan, UNHCR's regional spokesman Ron Redmond said cooking materials, blankets, mattresses, and sanitary supplies were delivered to almost 3,000 Syrians who fled the fighting in the past weeks and have been left homeless.

- AP