In a statement, the UN chief expressed his outrage at reports that civilians in the last opposition-held area of Rural Damascus have continued to be targeted by toxic agents.

The Secretary-General’s call comes after UN Special Envoy for Syria, Staffan de Mistura, told the Security Council late Monday that at least 49 people had been killed, and hundreds were injured in an alleged chemical attack in Douma on Saturday evening.

Mr. Guterres condemned the incident as “abhorrent” – echoing a statement issued in March – amid what he called “persistent allegations” of the use of chemical weapons in Syria.

In both statements, the UN chief underlined his support for the Organization for the Prohibition of Chemical Weapons (OPCW) – the body which investigates allegations of such attacks.

His latest statement also underlined his call for the Council to “redouble its efforts” to uphold norms against chemical weapons and agree on a mechanism that would ensure accountability.

UN agencies sound alarm over rising civilian casualties, new displacement

Meanwhile, in Geneva on Tuesday, UN humanitarian agencies expressed alarm at ongoing violence in several areas of Syria which has caused the mass displacement of civilians to spiral.

Asked by journalists about the alleged chemical attacks, both the World Health Organization (WHO) and the UN Office for the Coordination of Humanitarian Affairs (OCHA) said they were not in a position to confirm anything.

OCHA spokesperson Jens Laerke confirmed that aid workers were in place in eight shelters for the displaced, but not in Douma, site of the alleged attack:

“I’m not sure everyone understands that, we are not in Douma, Eastern Ghouta is still under siege. Occasionally we are able to go in with a convoy and we leave again immediately. We are in place outside of Eastern Ghouta in those eight centres where we can provide some aid. We are not in Eastern Ghouta. And for these, as you say, extremely serious allegations with very severe ramifications; political, military and otherwise, we need to be absolutely sure that what we say is correct.”

According to UN refugee agency, tens of thousands of people remain trapped in Douma and nearly a quarter of a million people need aid urgently in the wider Eastern Ghouta area.

More than 133,000 people have fled Eastern Ghouta in the past month and one third of that number have been given shelter in eight centres in Rural Damascus.

But these are “overcrowded and pose a serious health risk,” Andrej Mahecic from the Office of the UN High Commissioner for Refugees (UNHCR) said, adding that there and elsewhere in the war-torn country the situation is “desperate.”

UNHCR’s response involves providing essential aid, shelter support and protection services, including to 137,000 Syrians displaced from the Afrin region in the north.