The World Health Organization Director-General Tedros Adhanom Ghebreyesus on Sunday expressed alarm after a Palestinian humanitarian group announced that Israeli forces have ordered the immediate evacuation of Al-Quds Hospital in the Gaza Strip.

The report from the Palestine Red Crescent Society (PRCS) “is deeply concerning,” the WHO chief said on social media. “We reiterate it’s impossible to evacuate hospitals full of patients without endangering their lives. Under international humanitarian law, healthcare must always be protected.”

The humanitarian group explained in a statement Sunday that “two phone calls were received, with a clear and direct threat, that the hospital must be evacuated at once; PRCS holds full responsibility for the lives of everyone inside the hospital.”

PRCS highlighted that along with its staff, the hospital “has hundreds of wounded and patients receiving medical care,” including in the intensive care unit and children in incubators, along with approximately 12,000 internally displaced civilians sheltering there.

The group called for the International Committee of the Red Cross (ICRC) intervention to ensure the protection of civilians and PRCS’ teams and facilities in accordance with international humanitarian law, and for the global community, including the United Nations system, “to act immediately” to prevent the targeting of all Gaza hospitals and “a humanitarian catastrophe from unfolding.”

Israel launched a three-week bombardment of Gaza in response to a Hamas-led attack that killed 1,400 Israelis—with about 200 others taken hostage—and has now moved to a “second stage” of what some legal scholars are calling genocide, stepping up ground operations in the Palestinian territory as people around the world demand a cease-fire.

Israel’s war on Hamas-controlled Gaza—which has been under an Israeli blockade for 16 years—has killed over 8,000 people, including more than 3,300 children, displaced the majority of the 2.3 million population, knocked out internet and communication services, and devastated civilian infrastructure, including homes, schools, religious buildings, and medical facilitates.

Israeli forces—backed by billions in U.S. military support—previously threatened the Al-Quds Hospital and demanded an evacuation earlier this month, according to PRCS. As BBC reported at the time:

A doctors’ group, Physicians for Human Rights Israel, said it filed a petition to Israel’s Supreme Court warning that Al-Quds Hospital could not be evacuated.

“In its response, the state announced that it would not attack the hospital for the time being,” the group said, as it warned against harming civilians during combat, violating international law, and damaging medical services.

Dr. Ghassan Abu-Sittah, who recently left his London home to treat patients at Al-Shifa Hospital in Gaza, toldDemocracy in Exile this week that “basically, there’s just no possibility of evacuating any of the hospitals. First, it’s a war crime to even target hospitals, and threatening to do it, to evacuate people, does not make it less than a crime. It’s just not possible. Shifa Hospital has around 1,700 critically wounded patients. What are we going to do with them? Where are we going to take them?”

“We’re looking at days for the hospital to run out of fuel. If it does, then effectively the hospital becomes a mass grave,” the surgeon added. “We have 150 patients ventilated. You have a neonatal intensive care unit. You have anesthetic machines that can no longer work to do the surgeries. Without electricity, this is just a mass grave.”

ICRC president Mirjana Spoljaric said in a statement Saturday “I am shocked by the intolerable level of human suffering and urge the parties to the conflict to de-escalate now. The tragic loss of so many civilian lives is deplorable. It is unacceptable that civilians have no safe place to go in Gaza amid the massive bombardments, and with a military siege in place, there is also no adequate humanitarian response currently possible. This is a catastrophic failing that the world must not tolerate.”

“In the face of this dramatic armed conflict, what is critically needed now is adherence to international humanitarian law by all parties,” Spoljaric continued. “An unhindered flow of humanitarian relief and personnel into Gaza is vital, as is the capacity to get basic services on their feet again. Sustained humanitarian access is imperative, and aid workers must be able to operate in a safe environment.”

Dr. Christos Christou, international president of Doctors Without Borders or Médecins Sans Frontières, similarly stressed in a statement that “helpless people are being subjected to horrific bombing.”

“Families have nowhere to run or to hide, as hell is unleashed on them,” he said. “Water, food, fuel, medical supplies, and humanitarian aid in Gaza need to be urgently restored. We need a cease-fire now.”

“We are ready to increase our aid capacity in Gaza,” Christou added. “We have teams on standby ready to send medical supplies and to enter Gaza to support the emergency medical response, as soon as the situation allows it. But as long as the bombing continues with the current intensity, any effort to increase medical aid will inevitably fall short.”