The Syrian military said on Saturday that rebels had entered large parts of Aleppo city during an offensive in which dozens of soldiers had been killed, forcing the army to redeploy - the biggest challenge to President Bashar al-Assad in years.

Syrian opposition forces have taken control of much of the country’s second largest city Aleppo, according to video verified by CNN and residents in the city. A rebel alliance launched a surprise attack this week,

Rebel forces opposing President Bashar al-Assad have launched their biggest offensive in years this week, controlling a majority of Syria's second city of Aleppo according to a monitor.Along with Iran,