Over a few days, rebel fighters in northern Syria have launched incursions into several major cities with little resistance from government troops.

The Syrian army said Saturday that dozens of its soldiers had been killed in a major attack led by Islamist Hayat Tahrir al-Sham rebels who swept into the city of Aleppo, forcing the army to redeploy in the biggest challenge to President Bashar Assad in years.

The surprise attack, led by the Islamist group Hayat Tahrir al-Sham, was the boldest rebel assault for years in the civil war that has been frozen.

Rebel forces launched the largest offensive against the Syrian government in years on Wednesday. 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,

Rebel forces in Syria have seized control of most of the city Aleppo after launching a surprise offensive against government forces, a war monitor reported on Saturday as Russia says it deployed fighter jets against rebels in Syria.

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.

The insurgent offensive, shocking for its speed, has posed the most serious challenge to President Bashar al-Assad in years.

Video posted by pro-opposition media in Syria shows militants in Aleppo’s western suburbs removing the Syrian national flag from a monument.

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.