Health services in southern Gaza Strip have only two to three days of fuel supply left, the World Health Organization (WHO) warned on Wednesday as Israeli forces took control of Gaza's crucial Rafah border crossing.

Speaking to a media briefing in Geneva, Switzerland, WHO director-general Tedros Adhanom Ghebreyesus said the UN health agency is "deeply concerned about Israel's increased military activities in Rafah, where most of Gaza's people have fled for safety."

Dr Richard Peeperkorn, WHO's Representative of occupied Palestinian territory, said humanitarian work in the enclave is grappling with an acute shortage of fuel.

"Maybe the most important element, what we all need, humanitarians, is fuel, fuel, fuel. Then, of course, also for humanitarian aid but also staff movement and medevac," he said.

"Without fuel all the humanitarian operations, including hospital operations, they come to a halt. In the south, our estimation is that the hospitals only have fuel for two to three days left," Peeperkorn stressed.

Following the collapse of ceasefire talks in Egypt's Cairo, an Israeli official stated on Thursday that the Israeli army will persist in their operation in the southern Gaza Strip city of Rafah.

U.S. President Joe Biden's announcement that he would withhold arms supplies if Israel proceeded with its assault on Rafah drew a defiant reaction on Wednesday, alongside unease at the possible longer-term fallout from the open clash with Israel's most vital ally.

SHOTLIST:

FILE: Geneva, Switzerland - Date Unknown
1. Various of WHO headquarters, logo;

Rafah City, Gaza Strip - May 9, 2024 (CCTV - No access Chinese mainland)
2. Various of medical workers moving patient;
3. Various of patients in hospital;
4. Patient being sent into temporary tent;
5. Medical workers taking care of patients.

[RESTRICTIONS: No access Chinese mainland]