UN 'failed to prevent' Syria crimes: opposition

Nasr al-Hariri, president of the Syrian Negotiation Commission (SNC) blamed the UN for the crimes taking place in the war-torn country, while speaking to reporters in Riyadh.

"We hold the United Nations, the Security Council and the international community ... directly responsible for their silence around these crimes and for failing to take action to prevent these crimes," al-Hariri said.

"But let us not forget that the party that holds direct responsibility for the crimes are the Syrian regime and the countries that continue to stand by it".

The comments came as Russian-backed Syrian regime forces continue to wage a blistering assault on Eastern Ghouta.

The regime has retaken 70 percent of the enclave near Damascus since February 18.

On Saturday, reports said government forces seized Kafr Batna and Sabqa in the south of the enclave.

Meanwhile, at least 30 casualties occurred in Eastern Ghouta on Saturday morning after regime airstrikes targeted the village of Zamalka. 

The strikes came amid Russian reports that over 7,000 people alone had fled the besieged enclave on Saturday morning.

The offensive has killed around 1,400 civilians, according to the Syrian Observatory for Human Rights, a Britain-based war monitor which relies on a network of sources on the ground.

The assault has sparked an exodus with more than 40,000 civilians pouring into surrounding government-held areas over the past 48 hours.

The Syrian conflict began when the Baath regime, in power since 1963 and led by Assad, responded with military force to peaceful protests demanding democratic reforms during the Arab Spring wave of uprisings, triggering an armed rebellion fuelled by mass defections from the Syrian army.

According to independent monitors, hundreds of thousands of civilians have been killed in the war, mostly by the regime and its powerful allies, and millions have been displaced both inside and outside of Syria.

The brutal tactics pursued mainly by the regime, which have included the use of chemical weapons, sieges, mass executions and torture against civilians have led to war crimes investigations.

Agencies contributed to this report.