Israeli forces have raided the largest hospital in the Gaza Strip that is still functioning, amid warnings from the UN aid chief that a threatened ground offensive in Rafah, the area’s last remaining place of relative safety, could trigger an exodus of refugees fleeing into Egypt. Nasser hospital, in the central town of Khan Younis, was hit directly by tank fire overnight, staff at the medical complex said on Thursday, in an attack that killed one person and injured eight more. Dr Khaled al-Serr, a surgeon at the hospital, said in an Instagram post that Israel Defense Forces (IDF) ground troops stormed the premises about an hour later and began forcing patients, medical personnel and displaced civilians sheltering at the hospital to flee. Videos posted by Serr and others who said they were at the medical complex showed dripping water mixed with blood on the floor, and dust and smoke filling the air, as people searched for survivors under the rubble using lights on their phones. Shooting could be heard in the background. The UN’s humanitarian office had said on Wednesday that Nasser had been besieged by Israeli forces, with allegations that sniper fire had been aimed at the facility. On Wednesday night, a doctor in the hospital’s emergency department, Haitham Ahmad, told colleagues in the UK: “We’re living through fear and anxiety amid attempts to evacuate the people sheltering in the hospital. Many civilians have been shot by snipers, most of them within the hospital parameters. “We’re panicking. We woke up today to loud airstrikes and explosions to the north. It’s terrifying. We’re running on little food, and medicines are limited. We have patients in ICU with no chance of survival if we are forced to flee.” On Thursday morning, the IDF confirmed it had entered the hospital, describing the raid as “precise and limited” and based on intelligence that Hamas militants were using the complex and may have kept hostages there. A spokesperson for the Islamist movement dismissed the allegations as “lies”. The Israeli military later said it had apprehended suspects at Nasser and its operations there were continuing. The IDF’s spokesperson, R Adm Daniel Hagari, said one objective was to ensure the hospital could continue treating patients and that “we communicated this in a number of conversations we had with the hospital staff”. He added that there was no obligation to evacuate. The Hamas-controlled territory’s health ministry spokesperson, Ashraf al-Qidra, said the hospital would run out of fuel in the next day and that this would endanger the lives of six patients in intensive care and three babies in the neonatal ward. It is believed most of those who were able to flee the hospital had done so on Wednesday, with local health officials reporting that about 2,000 people arrived in the southern border town of Rafah overnight, while others went north, to Deir al-Balah. The charity Médecins Sans Frontières said people faced an impossible choice to stay “and become a potential target” or leave “into an apocalyptic landscape” of bombings. A member of its staff had been detained at an Israeli checkpoint after leaving Nasser, the organisation said on Thursday. Mohammad al-Moghrabi, who had been sheltering in the compound, said some people who attempted to leave on Wednesday were shot at and so returned to the hospital. “This morning they said there was a safe passage, so we left, but it wasn’t safe. They approached us with a bulldozer and a tank, they insulted us and left us for four hours under the sun,” he told Reuters. Dozens of Israeli attacks on struggling hospitals in the Gaza Strip during the latest war in the besieged coastal territory, now in its fifth month, have been condemned as a breach of international humanitarian law. Almost all medical centres in Gaza quickly became places of refuge for thousands of people fleeing the Israeli military’s massive bombardment campaign, as it was thought hospitals would be safe. Israel says the militants’ use of medical facilities to hide out or use as bases for launching operations makes the sites legitimate targets. The IDF has found underground tunnels in the vicinity of hospitals in Gaza, including al-Shifa in Gaza City, formerly the territory’s largest medical centre. However, journalists and human rights organisations have been unable to verify Israeli claims that medical buildings have been used as cover for major Hamas command-and-control centres. The attack on Nasser hospital came as international criticism of Israel’s planned ground offensive on the border town of Rafah mounted. Martin Griffiths, the UN’s aid chief, said in a media conference in Geneva on Thursday that the notion that people in Gaza could evacuate to a safe place was an “illusion”. Israel’s prime minister, Benjamin Netanyahu, has vowed to press ahead with an offensive on Rafah in the hunt for Hamas’s leaders, but only after civilians are allowed to leave the “battle zones”. The Israeli leader did not make clear where the trapped civilians would be permitted to go, and what safeguards, if any, would be put in place to protect them. More than a million Palestinians – nearly half of Gaza’s population – are sheltering in the city. On Wednesday, the Egyptian non-governmental organisation Sinai Foundation for Human Rights reported that construction work had begun on creating a “high-security gated and isolated area” near the border with Gaza “in the case of the mass exodus of the citizens of Gaza Strip”. Cairo has expressed alarm that an Israeli push into Rafah could force Palestinians to flee into the Sinai, potentially collapsing the historic peace treaty between Egypt and Israel that laid the foundations for the modern geopolitical architecture of the region. There is also widespread concern among Arab governments, especially Jordan, that an offensive on Rafah spilling into the holy month of Ramadan could spark explosive unrest in occupied East Jerusalem and the West Bank, where violence has already reached a 20-year high. Rishi Sunak, the UK prime minister, joined the series of world leaders urging Israel to hold back from launching a ground offensive. In a call with Netanyahu on Thursday, Sunak said he “was deeply concerned about the loss of civilian life in Gaza and the potentially devastating humanitarian impact of a military incursion into Rafah”, according to No 10. He reiterated: “The immediate priority must be negotiating a humanitarian pause to allow the safe release of hostages and to facilitate considerably more aid going to Gaza, leading to a longer-term sustainable ceasefire. For there to be lasting peace, Israel’s security must be assured.” This week’s diplomatic efforts in Cairo mediated by Egypt, Qatar and the US continue with the aim of salvaging a new hostage and ceasefire deal, but have yet to make any significant progress. It is widely believed that Netanyahu is slow-walking the talks because he is likely to be ousted from office in new elections when the war ends. The longtime leader faces several continuing corruption trials. Local media reported on Thursday that the prime minister snubbed other members of the war cabinet in taking an executive decision not to allow an Israeli delegation to return to Cairo, citing the “delusional” demands that Hamas had made for a truce as the reason for his decision. Israel’s war in Gaza was sparked by Hamas’s unprecedented offensive of 7 October last year, in which about 1,140 people were killed and another 250 abducted as bargaining chips. The Israeli offensive has killed more than 28,500 people, displaced more than 85% of Gaza’s population and reduced more than half of the territory’s infrastructure to rubble. The World Food Programme says one in four people are facing extreme hunger. The health authority in Gaza does not distinguish between civilian and militant deaths. Also on Thursday, the IDF said it had carried out an airstrike that killed a Hamas commander who participated in the 7 October attack and had held captive a female Israeli soldier subsequently killed by the group. Separately, medical officials said an Israeli strike had killed three Palestinians in a car in Gaza City. Their identities were not immediately clear. An Israeli soldier was also killed in fighting in the south of the strip, bringing the IDF’s total losses since the ground incursions began to 235.