The 13-year civil war in Syria has roared back into prominence with a surprise rebel offensive on one of Syria’s largest cities and ancient business hub.

Scores of people were killed after forces opposed to the government of President Bashar al-Assad overtook a Syrian military base, a monitoring group reported.

Several armed Syrian opposition groups have taken control of almost all of Aleppo, the second largest city in Syria, according to a war monitoring group and reports from the city. Why it matters: The breach of Aleppo is a dramatic shift in the 13-year Syrian civil war and the rebels' largest offensive since 2020.

Syria state media say government troops are battling insurgents inside the country’s largest city Aleppo for the first time since 2016

The lightning assault on Aleppo by the Islamist militant group Hayat Tahrir al-Sham abruptly redrew the front lines of Syria’s civil war.

A rebel commander said a fall in Iran-backed manpower created an opening this week's assault. Iran's ally Hezbollah has suffered big losses to Israel.