A still image taken on August 2, 2016 from a video said to be taken on August 1, 2016 posted on social media shows a man sitting breathing through a mask in what is said to be in Saraqeb, Idlib province, Syria. Social Media/Handout via Reuters Tv

A still image taken on August 2, 2016 from a video said to be taken on August 1, 2016 posted on social media shows a man sitting breathing through a mask in what is said to be in Saraqeb, Idlib province, Syria. Social Media/Handout via Reuters Tv

A still image taken on August 2, 2016 from a video said to be taken on August 1, 2016 posted on social media shows a man sitting breathing through a mask in what is said to be in Saraqeb, Idlib province, Syria. Social Media/Handout via Reuters Tv

August 2, 2016 10:18 AM (UTC+8)