Both Syria and Russia have said reports of the attack were fabricated by rebels and rescue workers in Douma and have accused the United States of seeking to use it as a pretext to attack the government.
Giuseppe D'Amato reports from Moscow.
People walk amongst destruction in the newly-captured town of Zamalka town, Eastern Ghouta, in the countryside of Damascus, Syria, 11 April 2018. Source: AAP Image/ EPA/YOUSSEF BADAWI