Some 9,000 patients in the Gaza Strip require evacuation for emergency care, with the war-torn Palestinian territory down to just 10 barely functioning hospitals, the head of the WHO said Saturday.

"With only 10 hospitals minimally functional across the whole of #Gaza, thousands of patients continue to be deprived of health care," World Health Organization Director-General Tedros Adhanom Ghebreyesus wrote on X.

Before the war, Gaza had 36 hospitals, according to the WHO.

"Around 9,000 patients urgently need to be evacuated abroad for lifesaving health services, including treatment for cancer, injuries from bombardments, kidney dialysis, and other chronic conditions," he said.

That is up from 8,000 in the WHO's previous assessment at the beginning of March.

Israel vowed to eliminate Hamas after the Islamist group's unprecedented October 7 attack on Israel and has been bombing Gaza without respite, damaging many healthcare facilities.

Violent ground combat has also been underway for weeks, sometimes around Gaza's hospitals, which are also providing refuge for thousands who have lost their homes or fled the fighting.

Gaza is subject to an almost complete blockade, and NGOs and the United Nations accuse Israel of preventing the delivery of humanitarian aid needed by the 2.4 million inhabitants who are mostly massed in Rafah at the territory's southern tip.

Israel has defended its policies as it pursues its stated goal of destroying Hamas, saying the UN should send more aid to Gaza, pushing back on reports by the UN and NGOs that cumbersome Israeli inspections are blocking food and other essentials.

The war began with Hamas's October 7 attack that resulted in about 1,160 deaths in Israel, mostly civilians, according to an AFP tally of Israeli official figures.

Palestinian militants also seized about 250 hostages. Israel believes around 130 remain in Gaza, including 34 who are presumed dead.

Israel's retaliatory campaign has killed at least 32,705 people, mostly women and children, according to Gaza's Hamas-run health ministry.

Tedros said that "so far, over 3,400 patients have been referred abroad through Rafah, including 2,198 wounded and 1,215 ill. But many more need to be evacuated.

"We urge Israel to speed up approvals for evacuations so that critical patients can be treated. Every moment matters."

Before the war, 50 to 100 patients a day were transferred to East Jerusalem or the West Bank, half of them for cancer treatment.