The World Health Organization has called for immediate humanitarian access to the Gaza Strip, warning Israel’s blockade and bombardment have left the enclave’s health system at “breaking point”.

Noting Gaza’s overstretched hospitals had only a few hours of electricity a day, with fuel being rationed to maintain critical services including intensive care, and X-ray and dialysis services, the United Nations’ health agency called for the opening of a humanitarian corridor to allow health workers into the territory, as well as the evacuation of the sick and injured.

It said shortages of medical supplies were also severe and that time was running out to prevent a humanitarian disaster in a territory that is home to more than two million people.

“Without the immediate entry of humanitarian aid into Gaza – especially health services, medical supplies, food, clean water, fuel, and non-food items – humanitarian and health partners will be unable to respond to urgent needs of people who desperately need it,” the agency said in a statement late on Thursday. “Each lost hour puts more lives at risk.”

The International Committee of the Red Cross (ICRC) also raised concern about the deteriorating situation in Gaza, describing the situation as “abhorrent”.

“As Gaza loses power, hospitals lose power, putting newborns in incubators and elderly patients on oxygen at risk. Kidney dialysis stops, and X-rays can’t be taken,” Fabrizio Carboni, the regional director for the Near and Middle East for the ICRC said in a statement on Friday. “Without electricity, hospitals risk turning into morgues.”

Israel has said it has dropped about 6,000 bombs on Gaza since it began its bombardment almost a week ago following an attack by the armed Hamas group that caught its security forces off-guard and killed more than 1,300 Israelis.

At least 1,500 Palestinians have been killed in the subsequent onslaught and thousands more injured as Israel prepares for a possible ground assault on the enclave.

Gaza has about 30 hospitals, 13 of them operated by the Ministry of Health and others privately run.

The WHO said it had documented 34 attacks on healthcare services in Gaza since Saturday. By yesterday, 11 WHO health workers had been killed while 16 were injured. Another five ICRC workers were killed. The WHO said 20 ambulances had also been hit.

The agency called for the immediate opening of the Rafah border crossing on the border with Egypt.

“WHO is ready to immediately dispatch trauma and essential health supplies … to ensure that they can reach the Gaza Strip via the Rafah border crossing,” the WHO said. “Urgent access through the crossing is essential so that WHO and other humanitarian agencies can act quickly to help save lives.”