Syrian government shelling of rebel enclave kills nearly 100

Heavy Syrian government bombardment of rebel-held Eastern Ghouta killed at least 94 civilians and wounded more than 300 over 24 hours, a monitor said, as government forces appeared to prepare for a ground assault.

The Syrian Observatory for Human Rights said air strikes battered the town of Hammuriyeh in Eastern Ghouta, leaving nine civilians dead.

The UK-based monitor's chief, Rami Abdel Rahman, said the civilian death toll from Monday's bombardment of the enclave outside Damascus was the heaviest since early 2015.

Held by rebels since 2012, Eastern Ghouta is now the last opposition-controlled pocket around Damascus.

Syrian President Bashar al-Assad has dispatched reinforcements there in recent weeks in an apparent bid to retake the region.

The Observatory and Syrian daily newspaper Al-Watan had said negotiations were underway for the evacuation of militants from the enclave. 

But government forces ramped up military pressure on Eastern Ghouta starting on Sunday, sending more than 260 rockets sailing onto opposition-controlled towns there. 

The bombing continued on Monday, sending terrified civilians in the enclave searching for cover, AFP's correspondents said.

With the bombardments continuing, a number of foreign governments have stepped up their rhetoric against the Assad government.

US National Security Adviser HR McMaster said on Saturday that, despite denials, public reports show Assad was using chemical weapons, and added that it was time for the international community to hold the Syrian government to account.

"Public accounts and photos clearly show that Assad's chemical weapons use is continuing," McMaster said at a major international security conference taking place in Munich.

"It is time for all nations to hold the Syrian regime and its sponsors accountable for their actions and support the efforts of the Organisation for the Prohibition of Chemical Weapons," he said.

McMaster did not specify which public accounts or pictures he was referring to.

Earlier this month, US Defence Secretary Jim Mattis said the Syrian government had repeatedly used chlorine gas, but stressed that the US did not have evidence of sarin gas use.

French President Emmanuel Macron has said that "France will strike" if chemical weapons are used against civilians in the Syrian conflict in violation of international treaties, but that he had not yet seen proof this is the case.

The Syrian government has repeatedly denied using chemical weapons and said it targets only armed rebels and militants.

In recent weeks, rescue workers, aid groups and the United States have accused Syria of repeatedly using chlorine gas as a weapon against civilians in Ghouta and Idlib.

Diplomatic efforts have made scant progress towards ending a war now approaching its eighth year, which has killed hundreds of thousands of people and forced half the pre-war Syrian population of 23 million from their homes.