The Hayat Tahrir al-Sham rebel group in Syria has taken control of much of Aleppo city after local forces withdrew to organize a counteroffensive to retake Aleppo.

By Saturday, they had taken control of "large parts" of the country's second-biggest city, Aleppo. The surprise offensive prompted the first Russian strikes on Aleppo since 2016, and saw Syria's military withdraw its troops from the city.

Syrian rebels launched a surprise offensive into western Aleppo, challenging years of government control and reigniting fears in a war-weary city.

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.