His call came just hours before UN agencies reported that phone lines, internet and mobile service in Gaza went down.

"Gaza has lost contact with the outside world amid reports of intensified bombardment," Lynn Hastings, the UN Resident and Humanitarian Coordinator in Palestine, wrote on X, formerly Twitter.

The World Health Organization (WHO) has "lost touch with our staff in Gaza, with health facilities, health workers and the rest of our humanitarian partners on the ground," Director-General Tedros Adhanom Ghebreyesus also wrote on the social media platorm.

"This siege makes me gravely concerned for their safety and the immediate health risks of vulnerable patients," he said. "We urge immediate protection of all civilians and full humanitarian access."

Catherine Russell, head of the UN Children’s Fund (UNICEF), voiced concern over the safety of colleagues and the one million children in Gaza, saying that "All humanitarians and the children and families they serve MUST be protected."

Fuel supply critical

In his statement, the Secretary-General said that life-saving humanitarian aid – food, water, medicine, fuel – must be allowed to reach all civilians in Gaza "swiftly, safely and at scale."

He noted that about 500 trucks per day were crossing into Gaza before the hostilities began, compared to the recent average of 12 trucks per day “despite needs being far greater than at any time before.”

However, the supplies that have trickled in do not include fuel for UN operations – essential to power hospitals, water desalination plants, food production and aid distribution.

“Given the desperate and dramatic situation, the United Nations will not be able to continue to deliver inside Gaza without an immediate and fundamental shift in how aid is going in,” he warned.

Mr. Guterres called for the verification system for the movement of goods through the Rafah crossing from Egypt to be adjusted to allow many more trucks in without delay.

“We must meet the expectations and core needs of civilians in Gaza,” he said.

‘A moment of truth’

The Secretary-General has welcomed the growing global consensus for a humanitarian pause in the conflict.

“I repeat my call for a humanitarian ceasefire, the unconditional release of all hostages, and the delivery of lifesaving supplies at the scale needed,” he said.

He warned that without a fundamental change, the people of Gaza will face an unprecedented avalanche of human suffering

“Everyone must assume their responsibilities. This is a moment of truth. History is judging us all.”

Meeting with Iran

In related developments, the UN chief met with Iran’s Foreign Minister Hossein Amir-Abdollahian, on Friday afternoon.

"The Secretary-General expressed to the Foreign Minister the importance of the Iranian contribution towards the unconditional and immediate release of hostages held in Gaza, and for the efforts being made to avoid a regional spill-over of the conflict and, in particular, in relation to Lebanon," according to a readout from his Office.

No fuel, no bread: WFP

The World Food Programme (WFP) also highlighted how severe fuel shortages threaten humanitarian operations in Gaza.

“Without additional fuel supplies, bakeries working with WFP will no longer be able to produce bread. Only two of our contracted bakeries have fuel to produce bread at the moment and tomorrow there might be none,” WFP Representative in Palestine Samer Abdeljaber said on Friday.

“This would be a terrible blow to the thousands of families living in shelters who have been relying on the daily bread deliveries.”

WFP echoed the Secretary-General’s call for a humanitarian ceasefire, underlining the need for continuous aid delivery to Gaza.

$80 million health appeal

Meanwhile, WHO is seeking $80 million to respond to needs in the occupied Palestinian territory (oPt), particularly Gaza, and for contingency planning for Egypt, Lebanon, Syria and Jordan.

The funding will be used to scale-up trauma and emergency care services, maintain access to essential health services and treatment of chronic conditions, establish disease surveillance and outbreak control measures, and ensure coordination of response.

WHO issued a statement noting that the conflict in Israel and the oPt has caused a large number of civilian deaths and injuries.

Fear of outbreaks, spillover

Hospitals in Gaza have been operating far beyond capacity due to a rise in the number of patients as well as displaced persons seeking shelter. The situation is unfolding amid airstrikes and a lack of medical supplies, food, water and fuel.

Overall, 1.4 million people have been uprooted and “massive displacement to shelters with inadequate resources will result in disease outbreaks,” WHO said.

Furthermore, there have been 171 attacks on healthcare in the oPt since the start of hostilities on 7 October, leading to 493 deaths and 387 injuries, with 56 attacks impacting health facilities and 130 impacting health personnel.

“The escalation of hostilities has already spread to the West Bank, East Jerusalem, the Lebanon Israel border and Syrian Arab Republic, with a risk of spilling over to other countries in the region, including Jordan, the Islamic Republic of Iran, and Iraq,” the agency warned.

Explosions in Lebanon

Separately, the UN Interim Force in Lebanon (UNIFIL) reported hearing explosions on Friday in several parts of the south, and peacekeepers observed two mortar rounds landing at sea.

UN Spokesperson Stéphane Dujarric said the Mission also observed multiple flares and shells being fired in UNIFIL’s area of operations on Thursday.

"As we have been reporting, over the past few days, our firefighters are continuing to support the Lebanese authorities in extinguishing fires burning near Alma ash-Shaab and Naqoura," he told journalists in New York.

The fires have threatened UN positions and civilian properties and were a result of exchanges of fire along the Blue Line, the unofficial frontier between Israel and south Lebanon. UNIFIL continues to monitor the situation.