In a significant development, Syrian authorities closed Aleppo airport on Saturday, canceling all flights as rebel forces led by the Islamist group Hayat Tahrir al-Sham advanced into the city.

This marks their return nearly a decade after being expelled from Aleppo.

The rebel incursion, which began on Wednesday, has seen rapid advances through government-held areas.

Russia, a crucial ally of President Bashar al-Assad, pledged additional military assistance to Syria, with new equipment expected within 72 hours.

While opposition sources claim that Turkey sanctioned the offensive, Turkey's foreign ministry warns that recent attacks could undermine regional stability.

The Syrian military is engaged in heavy fighting around Aleppo and Idlib, with Syrian state media denying rebel entry into Aleppo city itself.

The conflict is the most significant since March 2020, coinciding with a de-escalation deal between Russia and Turkey.

David Carden of the U.N. expressed concern over the escalating violence in northwest Syria, citing at least 27 civilian casualties, including children.

Russia condemned the rebel attack, viewing it as a breach of Syria's sovereignty and supports Syria's efforts to restore order.

Reports indicate shelling resulted in the deaths of four civilians in Aleppo on Friday, including students at university dormitories.

The ongoing conflict highlights the region's continued volatility amidst broader geopolitical tensions.