Tanks have entered Gaza’s largest hospital complex as Israel carries out what it has called a “precise and targeted operation against Hamas”.

The development came just hours after the US said it concurred with Israel that parts of the al-Shifa hospital were being used by Hamas terrorists as a control centre and to hold some of the 240 hostages still missing after the Oct 7 attack on Israel.

Hamas said on Telegram it rejected US claims about its use of hospitals and that they “give a green light to the Israeli occupation to commit further brutal massacres targeting hospitals”.

It added: “We hold Israel and President Biden responsible for the Israeli army’s storming of the Shifa complex.”

“The IDF forces include medical teams and Arabic speakers, who have undergone specified training to prepare for this complex and sensitive environment, with the intent that no harm is caused to the civilians being used by Hamas as human shields,” the Israel Defence Forces (IDF) posted on social media.

An eyewitness inside the hospital told the BBC they saw commando soldiers enter the hospital’s main emergency department.

Khader Al Za’anoun, a reporter for the Palestinian news agency Wafa, told CNN media at the scene had witnessed Israeli tanks mounted with guns which were pointed towards the hospital. 

John Kirby, a National Security Council spokesman, earlier told reporters traveling with US President Joe Biden that Hamas and the Palestinian Islamic Jihad were using some hospitals and tunnels underneath them “to conceal and to support their military operations and to hold hostages”.

While declining to provide specifics, Mr Kirby added: “They have stored weapons there, and they’re prepared to respond to an Israeli military operation against that facility.”

He stressed, however, the US did not support attacking the hospital in bomb attacks.

“We do not support striking a hospital from the air,” Mr Kirby said. “And we do not want to see a firefight in a hospital where innocent people, helpless people, sick people are simply trying to get the medical care that they deserve, not to be caught in a crossfire. Hospitals and patients must be protected.”

Deputy Pentagon Press Secretary Sabrina Singh declined multiple times to expand on how the US came to have information on terrorists using the hospital, but said there were  “multiple agencies that collect and assess and analyse intelligence”.

Palestinian doctors at the hospital have insisted their only interest has been in treating the injured. The health ministry in Gaza, run by Hamas, says as any as 11,000 civilians have been killed by Israel’s military operations.

The UN’s office for humanitarian affairs, OCHA said in its flash update on Wednesday morning: “Hospitals and medical personnel are specifically protected under international humanitarian law and all parties to the conflict must ensure their protection.”

OCHA added: “Hospitals must not be used to shield military objectives from attack.”

IDF says it issued evacuation order

It is unclear precisely how many patients remain in Al-Shifa, though recent reports said it currently was looking after 500 patients and was the sole operational medical facility in in the north of the Gaza Strip.

Forty patients died in Shifa hospital on 14 November, according to the Ministry of Health in Gaza. The hospital reported preparations for a mass grave inside the compound to bury 180 bodies of patients, which cannot be evacuated due to the intense fighting.

On Tuesday, the World Health Organisation (WHO) praised the “heroic efforts” of staff at the hospital and expressed concern for hundreds of thousands of displaced people in the enclave.

In a statement issued by his spokesperson, UN Secretary-General António Guterres said he was “deeply disturbed by the horrible situation and dramatic loss of life” reported in Gaza’s embattled medical facilities.

“In the name of humanity, the Secretary-General calls for an immediate humanitarian ceasefire”, the statement said.

The operation at Al-Shifa, came after the IDF said it “publicly warned time and again that Hamas’ continued military use of the Shifa Hospital jeopardises its protected status under international law”.

“Yesterday, the IDF conveyed to the relevant authorities in Gaza once again that all military activities within the hospital must cease within 12 hours. Unfortunately, it did not,” it added.

Hamas has denied the Israeli accusations that it has used the hospital for cover.

The military operation came after Gaza’s health ministry warned in the early hours of Wednesday of a potential Israeli move, saying Israel informed Gaza health officials that its forces would raid the facility.

The ministry said in a statement: “We hold Israel’s raiding forces fully responsible for the lives of medical staff, patients and displaced people in Gaza’s Al Shifa Hospital.’’

In its post on social media the IDF said it had “facilitated wide-scale evacuations of the hospital and maintained regular dialogue with hospital authorities”.

It added: “We call upon all Hamas terrorists present in the hospital to surrender.”