Syrian President Bashar al-Assad on Thursday offered an amnesty to armed rebels battling his forces if they surrender, the official SANA news agency reported.

"Everyone carrying arms... and sought by justice... is excluded from full punishment if they hand themselves in and lay down their weapons," SANA said, quoting a presidential decree on the three-month amnesty offer.

The reprieve also includes any rebel who frees a hostage, according to the decree text.

The offer comes as opposition neighbourhoods of Aleppo city are effectively surrounded by pro-government forces, sparking fears for the more than 200,000 people trapped there.

Assad's ally Russia said Thursday it had launched a "large-scale" operation with the Syrian government to open humanitarian corridors for civilians and fighters fleeing the northern city.

Read mkore at AFP.