Turkey and Russia have agreed a ceasefire plan for all of Syria that should come into force this evening at midnight, the state-run Anadolu news agency said on Wednesday.

The plan aims to expand a ceasefire in the city of Aleppo, brokered by Turkey and Russia earlier this month to allow the evacuation of civilians, to all of the country, it said.

But, like previous ceasefire plans that had been brokered by the United States and Russia, it excludes "terror" groups, the agency said.

If successful, the plan will form the basis of upcoming political negotiations between the regime and opposition overseen by Russia and Turkey in the Kazakh capital Astana, it added.