Syrian government and Russian airstrikes killed at least 17 people on Tuesday in rebel-held northwestern Syria in a spike in casualties from relentless daily strikes in recent months, witnesses and rescuers said.
The northwest corner of the country, including the Idlib region, is the last significant swathe of Syrian territory still in insurgent hands after eight and a half years of war.
Russia, which has backed President Bashar Assad against rebels and Islamist militants, and Turkey, long a supporter of rebels, co-sponsored a conflict "de-escalation" deal for the area earlier this year that has since faltered.