Cairo, 30 November 2024 (dpa/MIA) — Opposition fighters have seized control of most parts of Aleppo, Syria's second largest city, after launching a massive surprise offensive against the government forces, a war monitor reported on Saturday.

An alliance of rebel factions led by the Islamist militant organization Hayat Tahrir al-Sham (HTS) has advanced deep into  Aleppo and now controls the majority of the city, including government buildings and prisons, the Syrian Observatory for Human Rights said.

The city's governor and security commanders withdrew from the city centre, while government forces fled to a suburb, according to the Britain-based watchdog.

In an attempt to hamper the militants' advance, Russia, an ally of Syrian President Bashar al-Assad, unleashed overnight airstrikes on the city for the first time since 2016, the observatory said. 

The rebels' offensive marks a significant escalation in Syria's civil war, which has raged since 2011 and had recently seen relatively stable front lines.

HTS is considered one of the most powerful armed militias in north-western Syria.

Fighting broke out in north-western Syria on Wednesday pitting the opposition alliance against government forces, and forcing around 14,000 people to leave their homes, according to the United Nations.

The opposition assault is considered the largest by rebels on Aleppo since 2016 when they were ousted from the eastern areas of the city.

The fighting has resulted so far in a total of 301 deaths, including 28 civilians, the observatory reported.

Opposition factions announced the offensive on Wednesday and said it was a response to recent artillery shelling by government forces loyal to al-Assad, which targeted civilian areas.

The Syrian president, with the help of his allies Russia and Iran, has managed to regain control of about two-thirds of the country from rebels in the past years.

Idlib, southwest of Aleppo, is the last rebel stronghold in war-torn Syria.