There is enough fuel to run hospitals in the southern Gaza Strip for only three more days, the head of the World Health Organization (WHO) warns after Israeli forces seized control of the Rafah border crossing.

Israel on Tuesday sent ground troops and tanks into the city of Rafah and seized the nearby crossing into Egypt that is the main conduit for aid into the besieged Palestinian territory.

WHO Director-General Tedros Adhanom Ghebreyesus said fuel that the United Nations health agency had expected to be allowed in on Wednesday had been blocked.

Israeli authorities control the flow of humanitarian aid into Gaza.

“The closure of the border crossing continues to prevent the UN from bringing fuel. Without fuel all humanitarian operations will stop. Border closures are also impeding delivery of humanitarian aid into Gaza,” Tedros said on X, formerly Twitter.

“Hospitals in the south of Gaza only have three days of fuel left, which means services may soon come to a halt.”

Israel has threatened a major assault on Rafah to defeat thousands of Hamas fighters it says are holed up there. But the city is also a refuge for more than 1.4 million Palestinians who have fled combat farther north in the coastal enclave under Israel’s previous evacuation orders.

They have crammed into tent camps and makeshift shelters and have suffered from shortages of food, water and medicine. Rafah’s main maternity hospital, where nearly half of Gaza’s births take place, has stopped admitting patients, the UN Population Fund (UNFPA) told the news agency Reuters.

The UNFPA said the hospital, Al-Helal Al-Emairati Maternity Hospital, had been handling about 85 of the 180 births in Gaza each day before Israel’s incursion into the city.

Medical Aid for Palestine (MAP) said it had received an update from Marwan Homs, head of Abu Youssef al-Najjar Hospital in Rafah, who said the facility is no longer functioning because all staff have been ordered to evacuate.

“This was Rafah’s largest hospital,” MAP said.

“This means Rafah’s already overstretched and underresourced health system is now left with only Kuwaiti Hospital, which is an NGO hospital with around [a] 16-bed capacity; Marwani field hospital, which is only a trauma stabilisation point; and Al-Emairati Hospital, which is only a maternity hospital,” it added.

The dire warnings come as Palestinian officials in Gaza accused Israel of deliberately halting the entry of aid into Gaza and targeting medical facilities.

Israeli forces are “purposefully worsening the humanitarian situation by halting the entry of aid supplies from the Rafah and Karem Abu Salem border crossings, and by targeting hospitals and schools in eastern Rafah,” Salama Marouf, Gaza’s Government Media Office spokesman, told reporters, referring to the latter crossing by its Arabic name. It is also known as Kerem Shalom in Hebrew.

Israel says it does not restrict aid supplies into Gaza.

Hamas said its fighters were battling Israeli forces in the east of Rafah. The Israeli military said it troops had discovered Hamas infrastructure in several places in eastern Rafah and were conducting targeted raids on the Gaza side of the Rafah crossing and airstrikes across the Gaza Strip.

Israel has ordered tens of thousands of civilians, many of whom have been uprooted several times already, to go to an “expanded humanitarian zone” in al-Mawasi, some 20 km (12 miles) away. Rafah’s mayor Ahmed Al-Sofi said said the coastal area lacked all “the necessities of life”.

Residential neighbourhoods, hospitals and schools where tens of thousands of people have sought shelter “are being targeted” by Israeli forces in Rafah, Maarouf said.

“The reality in eastern Rafah governorate indicates a real humanitarian catastrophe,” he said.

More than 35 Palestinians have been killed in the latest 24-hour reporting period, according to health officials in the enclave.

Speaking alongside Maarouf, Khalil al-Daghran, an official with Gaza’s Ministry of Health, said the closure of the Rafah crossing has prevented dozens of wounded and ill Palestinians from leaving to seek treatment abroad and those who were cleared by Egypt to leave Gaza on Tuesday have been prevented from doing so.

The situation of Gaza’s sick and wounded is “very difficult” and has been this way since the start of the Israeli assault due to a severe lack of medical supplies, al-Daghran said.

He called on the international community and United States President Joe Biden’s administration to pressure Israel to end its assault and reopen the border crossings immediately.

About 50,000 people had left Rafah since Monday when the Israeli incursion began, an official with the UN Relief and Works Agency for Palestine Refugees (UNRWA) said.

UNRWA said an average of 200 people are leaving Rafah every hour – mainly to Deir el-Balah in central Gaza and to the widely destroyed southern city of Khan Younis.