JERUSALEM (JTA)—The latest alleged chemical attack on a town in Syria by government forces shows that the international organizations established after the Holocaust to prevent genocides have failed, a Yad Vashem official said.

Avner Shalev, chairman of the Holocaust memorial and museum in Jerusalem, also condemned the indifference of the world community to such “crimes against humanity.”

“In light of the horrific images emanating from Syria over recent days of the mass killings of civilians, including children, in the chemical attack, it would appear that the mechanisms and international bodies developed after the Holocaust to prevent the recurrence of crimes against humanity are failing,” he wrote in a statement released Tuesday by Yad Vashem.

“The terrible scenes we are witnessing, right across our border, are a result of and continue to occur due to the indifference of the world. I call on the global community not to stand on the sidelines, but to act determinedly to put an end to the human suffering and provide humanitarian aid to the victims.”

Shalev made his remarks ahead of Yom Hashoah, or Holocaust Remembrance Day, held annually in Israel on the anniversary of the Warsaw Ghetto Uprising.

At least 40 people were killed Saturday in an alleged chemical attack on the rebel-held town of Douma, located east of the capital, Damascus. Video footage released online Sunday showed the dead, including whole families, lying on floors with white foam around their mouths, signifying possible nerve agents. Other footage showed full clinics where workers were hosing down patients and treating them with respirators.

President Donald Trump on Monday called the attack “heinous” and promised a “forceful” response.