Syria's civil war reignites in dramatic fashion as Russia joins airstrikes on rebels who seized Aleppo

The Syrian military and its ally Russia conducted deadly joint air raids Monday on areas that Islamist-led rebels seized control of over the weekend. The strikes were a response to a lightning offensive by the rebels that saw them wrest control of swathes of northwest Syria from government forces.

The conflict that started more than a decade ago took a significant turn several days ago, catching many — including, it seems, Syrian dictator Bashar Assad and his Russian backers — by surprise. On Saturday, rebels, including many with the U.S.-designated Islamic terrorist group Hayat Tahrir Al-Sham (HTS), took control of the major city of Aleppo in northern Syria.

The rebels seized Aleppo's airport and started pushing into towns and villages in the countryside around the city on Sunday after leaving piles of dead government soldiers in the streets. Observers said the rebel forces were often met with little to no resistance by regime forces, but by Monday the pace of the surprise offensive appeared to have slowed, with Assad and his Russian backers ramping-up their response.