The World Health Organization on Wednesday demanded "immediate" access to the victims of an alleged chemical attack in Syria, voicing indignation at the strike that caused symptoms consistent with exposure to toxic substances.
"We should all be outraged at these horrific reports and images from Douma" where Saturday's attack took place, said Peter Salama, the UN agency's chief of emergency response.
"WHO demands immediate unhindered access to the area to provide care to those affected, to assess the health impacts, and to deliver a comprehensive public health response," he added.
Citing information previously released by local health organizations, WHO said that "an estimated 500 patients presented to health facilities exhibiting signs and symptoms consistent with exposure to toxic chemicals".
"There were signs of severe irritation of mucous membranes, respiratory failure and disruption to central nervous systems of those exposed," the statement added.
The United States, Britain and France have argued the incident bears all the hallmarks of a strike ordered by the regime of Syrian President Bashar al-Assad.
Assad has been blamed for previous attacks by the Organization for the Prohibition of Chemical Weapons (OPCW) and UN-backed war crimes investigators.
WHO has delivered medicine capable of treating certain types of chemical agents to clinics through a series of humanitarian convoys deployed across the country in recent years.
UN officials have also accused Assad's troops of at times removing those treatments from humanitarian vehicles.