Refugee crisis may escalate in Syria

Government forces and allies launch major offensive on Aleppo.

Hundreds of thousands of civilians could be cut off from food supplies if Syrian government forces succeed in their offensive to encircle rebel-held parts of Aleppo, the UN said, warning of a massive new flight of refugees.

Syrian government forces, backed by Russian air strikes and Iranian and Lebanese Hezbollah fighters, have launched a major offensive in the countryside around Aleppo, which has been divided between government and rebel control for years.