Chemical weapons used by the regime have killed hundreds of people in an attack on the eastern suburbs of Damascus, according to claims by activists in Syria. Estimates of the number of victims vary from 200 to more than a 1,000.

According to the Local Coordination Committees of Syria, poisonous gases infiltrated Ain Tarma and Zamalka in Eastern Ghouta and Mouadamieh in Western Ghouta.

Dozens of videos have been uploaded on YouTube showing corpses and victims struggling to breathe.

A state-run news agency denied reports of the use of chemical weapons, saying there is “no truth whatsoever” to the claims.

A UN team arrived in the country on 20 August with the mandate to inspect for the use of chemical weapons. So far, they have not released any statement as to whether they will be heading to Ghouta for investigations, though Argentina’s UN ambassador, Maria Cristina Perceval said council members “welcomed Secretary-General Ban Ki-moon’s determination to ensure a thorough, impartial and prompt investigation”.

A statement by UNICEF said reports of the attacks, presumably including children, are “deeply disturbing”.

“Such horrific acts should be a reminder to all the parties and all who have influence on them that this terrible conflict has gone on far too long and children have suffered more than enough. Children must be protected, and those who fail to protect them will be held accountable,” it said.