The World Health Organization (WHO) has accused "Israel" of blocking two humanitarian missions attempting to enter northern Gaza, where the besieged region is suffering from relentless attacks and a crumbling health system.

The missions, which aimed to evacuate critical patients and deliver essential fuel, blood units, and medical supplies, were forced to turn back due to Israeli checkpoints and other barriers, the WHO said on Thursday.

A total of seven such missions have been denied or obstructed this week.

The blockade comes amid "Israel’s" genocidal campaign in the Jabalia refugee camp and surrounding areas of northern Gaza, where Israeli forces have ordered residents to relocate to so-called "humanitarian zones" in the south.

However, Palestinian and UN officials have said that there are no safe areas in the densely populated strip.

The Israeli military also ordered the evacuation of several hospitals, including the Indonesian, Al-Awda, and Kamal Adwan hospitals, threatening patients and medical personnel with assault if they failed to comply.

Read more: 'Israel' attacks hospitals in Gaza, commits new massacres

WHO Director-General Tedros Adhanom Ghebreyesus called on "Israel" to stop the evacuation orders and to protect hospitals and humanitarian missions.

"North Gaza has barely any health services left. People have nowhere to go," he warned, calling for an immediate ceasefire to protect those trapped in the genocide.

Earlier, a United Nations inquiry accused "Israel" of committing war crimes, stating that "Israel" has been deliberately targeting medical personnel and facilities in Gaza, constituting the crime against humanity of extermination.

Navi Pillay, former UN High Commissioner for Human Rights and chair of the inquiry, said children have been disproportionately affected by the collapse of the health system.

According to the Palestinian Health Ministry, approximately 1,000 medics have been killed in Gaza over the past year, which the WHO called an "irreplaceable loss".

North Gaza hospitals out of service

For seven consecutive days, "Israel" has blocked fuel deliveries, leaving hospitals in critical condition, Gaza's Civil Defense spokesperson, Mahmoud Basal, told Al Mayadeen.

Only Kamal Adwan Hospital remains operational in the North, as others struggle to function without fuel.

"The residents in northern Gaza are suffering from a severe shortage of all basic needs—there is no water, no food, and no medicine," Basal said.

The spokesperson noted that Israeli drones are bombing anything that moves in Jabalia camp, putting civilians at even greater risk.

Read more: Gaza home to largest number of amputee children in modern history: UN

The Palestine Red Crescent Society (PRCS) in Gaza reported earlier that six of its ambulances were now out of service in northern Gaza due to fuel shortages and the continued Israeli blockade, further crippling emergency services in the area.

The blockade and relentless attacks are intensifying the already catastrophic humanitarian situation in Gaza.