Syrian rebels mount significant offensive against regime forces in Aleppo province.

 Syrian rebels mount significant offensive against regime forces in Aleppo province.

Syrian rebels have launched a large-scale offensive against regime forces in western Aleppo, marking the first major escalation between the two sides in years, according to a Free Syrian Army source and local residents.

The opposition factions announced the operation, dubbed “Deterrence of Aggression,” on their Telegram channel on Wednesday, stating it was in retaliation for recent artillery attacks by Syrian President Bashar al-Assad's forces.

In their statement, rebels claimed to have seized 13 villages, including the key towns of Urm Al-Sughra and Anjara, as well as Base 46, the largest regime military base in western Aleppo.

The rebels reported that 37 members of regime forces and allied militias were killed during the offensive.

CNN has not independently verified the casualty figures and has reached out to the Syrian government for comment.

Wednesday's unexpected attack marks the most significant clash between Syrian rebels and regime forces since March 2020, when a ceasefire was brokered by Russia and Turkey.

The Syrian rebels' Military Operations Command told CNN that its fighters had captured the town of Urm Al-Kubra, approximately 20 kilometers (12 miles) from Aleppo, after what it described as "intense battles with Assad forces and Iranian militias."

Spokesperson Hassan Abdulghani added that the group had “conducted a precision strike targeting a helicopter at Al-Nayrab Airport,” located east of Aleppo.

Videos circulating on social media, which CNN could not independently verify, show smoke billowing from the western Aleppo countryside, with rebel troops appearing to operate in several villages near Aleppo city. In one video, a fighter is seen praying and celebrating in Anjara, a village he claims as his hometown. “Anjara is ours, not the Assad family’s,” the cameraman is heard saying.

Syrian state media has not commented on the clashes, while some pro-regime outlets have acknowledged the fighting but provided no details on specific locations or outcomes.

A resident of a regime-held neighborhood in Aleppo city told CNN that civilians in New Aleppo, one of the country's wealthiest districts, have begun fleeing to other areas out of fear of the escalating violence.

The opposition factions involved in the offensive range from Islamist groups to the moderate Free Syrian Army, which previously received support from the United States and Turkey.

Syria’s civil war began in 2011 during the Arab Spring, when the Assad regime violently suppressed a pro-democracy uprising. Assad, who has been in power since 2000, faced a growing rebel movement, with the Free Syrian Army emerging to combat government forces.

The conflict escalated as regional and global powers, including Saudi Arabia, Iran, the United States, and Russia, became involved, turning the civil war into what some analysts called a “proxy war.” The chaos also allowed ISIS to gain a foothold in Syria before suffering major defeats.

Since a 2020 ceasefire brokered by Russia and Turkey, the conflict has been relatively subdued, limited to sporadic skirmishes between rebels and Assad’s forces. Over a decade of war has left more than 300,000 civilians dead and displaced millions across the region, according to the United Nations.