Twelve people were killed on Thursday by airstrikes and artillery fire in Syria's Idlib province, local civil defense sources said.
According to the White Helmets, a Syrian civil defense agency, Russian and Syrian regime warplanes repeatedly struck residential areas of the province.
White Helmets chief Mustafa Yusuf said the attacks had left at least 12 people dead in Idlib's Al-Lataminah and Babuline districts.
"Regime and Russian warplanes fired more than 150 rockets at various targets in Al-Lataminah," Yusuf said.
"They are also using internationally banned weapons, including vacuum bombs," he added.
Notably, Idlib falls within a network of de-escalation zones -- endorsed by Turkey, Russia and Iran -- in which acts of aggression are expressly prohibited.
Syria has only just begun to emerge from a devastating civil war that began in early 2011 when the Assad regime cracked down on pro-democracy protests with unexpected ferocity.
