People ride a motorcycle near damaged buildings in rebel-held Ain Tarma, eastern Damascus suburb of Ghouta, Syria September 17, 2016. REUTERS/Bassam Khabieh

A damaged wall of a school is pictured in rebel-held Ain Tarma, eastern Damascus suburb of Ghouta, Syria September 17, 2016. REUTERS/Bassam Khabieh

People walk across a street in rebel-held Ain Tarma, eastern Damascus suburb of Ghouta, Syria September 17, 2016. REUTERS/Bassam Khabieh

A damaged wall of a school is pictured in rebel-held Ain Tarma, eastern Damascus suburb of Ghouta, Syria September 17, 2016. REUTERS/Bassam Khabieh

A damaged wall of a school is pictured in rebel-held Ain Tarma, eastern Damascus suburb of Ghouta, Syria September 17, 2016. The text on the wall reads in Arabic:" The Baath vanguard." REUTERS/Bassam Khabieh

Federal Bureau of Investigation (FBI) officials stand amid evidence markers near the site of an explosion in the Chelsea neighborhood of Manhattan, New York, U.S. September 18, 2016. REUTERS/Rashid Umar Abbasi

New York City Police Department (NYPD) officers stand near the site of an explosion in the Chelsea neighborhood of Manhattan, New York, U.S. September 18, 2016. REUTERS/Rashid Umar Abbasi

A New York City Police Department (NYPD) truck tows a spherical chamber carrying a second explosive device from near the site of an explosion in the Chelsea neighborhood of Manhattan, New York, U.S. September 18, 2016. REUTERS/Rashid Umar Abbasi