A major military offensive by a radical Islamist group against Syrian government forces in northwestern Syria—the largest since 2020—prompted Russian and Syrian air forces to launch retaliatory airstrikes on Thursday.

Rebels, led by the U.S.-designated terrorist organization Hayat Tahrir al-Sham, attacked numerous towns and villages in Aleppo province, a region under the control of President Bashar al-Assad.

This offensive coincided with a ceasefire agreement reached between Assad’s ally, Hezbollah, and Israel, ending over a year of conflict.

The battle involves a complex array of actors: the Assad regime, Iran, and a Turkey-backed Islamist movement, all classified by the U.S. as state sponsors of terrorism.

Rebekah Koffler, a former U.S. defense intelligence officer and Putin expert, suggests this is a strategic move by Putin, a “lateral escalation” in response to the U.S. authorizing Ukraine to use long-range missiles against Russia. She argues Putin is aiming to pressure the U.S. to revoke this authorization, employing a “escalate to de-escalate” strategy, and leveraging the situation in Syria to gain negotiating leverage in Ukraine before a potential Trump presidency.

Koffler also warned of the possibility of Assad using chemical weapons.

Alex Grinberg, an Israeli Russia expert, notes that Assad’s forces heavily rely on Russian air power to combat Hayat Tahrir al-Sham.

Iranian state media reported the death of a senior IRGC military advisor, Brigadier General Kioumars Pourhashemi, in Aleppo during the incursion.

Rebel groups claim their actions were a response to recent Syrian and Russian airstrikes targeting civilians in southern Idlib and a preemptive measure against a perceived Syrian army buildup.

Assad’s war, which began with pro-democracy protests in 2011, has resulted in the deaths of over 500,000 people.

Iran has deployed thousands of fighters to Syria, including both official advisors and Shi’ite militiamen from across the region.

Turkish officials report that the rebels initiated a limited operation following attacks by Syrian government forces, expanding their assault after the government forces retreated.

Reuters contributed to this report.