Syrian and Russian jets are stepping up strikes on opposition forces in northern Syria in retaliation for the sudden offensive that has cost the regime control of the country’s second largest city, Aleppo.

As things stand this morning, the Syrian army says that anti-government forces have now taken control of "large parts" of Aleppo. Meanwhile, the country's president is vowing to "defend [Syria's] stability and territorial integrity in the face of all terrorists and their backers".

At least 25 people were killed in northwestern Syria in air strikes carried out by the Syrian government and Russia, the Syrian opposition-run rescue service known as the White Helmets said early on Monday.