A cessation of hostilities is due to start in Syria at sunset on Monday, September 12 after a weekend of air strikes, BBC News reports.

The 10-day truce is due to be followed by co-ordinated U.S. -Russian air strikes against jihadist militants.

Syrian state media reported that President Bashar al-Assad welcomed the deal, which was reached late on Friday in Geneva after months of talks between Russia and the U.S.

But it is unclear whether rebel factions will abide by it.

The Free Syrian Army group has written to the United States administration saying that while it would "co-operate positively" with the ceasefire, it was concerned it would benefit the government.

Another rebel group, the influential hardline Islamist Ahrar al-Sham, has rejected deal.

Ahead of the ceasefire, the Syrian government carried out heavy air strikes in several rebel areas over the weekend, killing about 100 people.

Russian warplanes have also been in action in the provinces of Idlib and Aleppo, say Syrian activists.

Such intensification of violence has occurred before other, aborted, ceasefires in Syria, BBC said.

The conflict in Syria, which began with an uprising against Assad, has raged for five years and claimed the lives of more than a quarter of a million people.

Millions have fled abroad, many of them seeking asylum in the EU, but nearly 18 million people remain in Syria, which has been carved up by fighting between government and rebel forces.