The UN Secretary General Antonio Guterres has struck a rare and powerful alarm bell in a letter to the Security Council warning that he expects public order "to completely break down soon" in besieged Gaza.

The comments came in a letter written by Guterres on Wednesday invoking Article 99 of the UN's charter, which states that "the Secretary-General may bring to the attention of the Security Council any matter which in his opinion may threaten the maintenance of international peace and security."

While calling for a "humanitarian ceasefire," Guterres wrote to the president of the Security Council that the humanitarian conditions amid Israel’s war on the blockaded enclave are "fast deteriorating into a catastrophe with potentially irreversible implications for Palestinians as a whole."

"Amid constant bombardment by the Israel Defense Forces, and without shelter or the essentials to survive, I expect public order to completely break down soon due to the desperate conditions, rendering even limited humanitarian assistance impossible," he said.

"An even worse situation could unfold, including epidemic diseases and increased pressure for mass displacement into neighbouring countries."

Ecuador currently holds the rotating presidency of the Security Council.

The Secretary General's spokesperson, Stephane Dujarric, called the move "very dramatic," noting that Article 99 hadn't been invoked in decades.

"He is invoking one of the few powers that the charter gives him," Dujarric said.

Israeli hardline Foreign Minister Eli Cohen said Guterres' tenure was "a danger to world peace".

"Guterres' tenure is a danger to world peace. His request to activate Article 99 and the call for a ceasefire in Gaza constitutes support of the Hamas terrorist organization," Cohen wrote on X, formerly Twitter.

'Impossible' conditions

Guterres, who took office in 2017, also urged the members of the Security Council to "press to avert a humanitarian catastrophe."

"The health care system in Gaza is collapsing," he said, adding that "there is no effective protection of civilians."

"The current conditions are making it impossible for meaningful humanitarian operations to be conducted," the letter said, adding that "nowhere is safe in Gaza."

The situation threatens "peace and security in the region," Guterres said.

"With a humanitarian ceasefire, the means of survival can be restored, and humanitarian assistance can be delivered in a safe and timely manner across the Gaza Strip."

"The international community has a responsibility to use all its influence to prevent further escalation and end this crisis," he said.

In mid-November, after four rejected draft texts, the heavily divided Security Council called for "extended humanitarian pauses" in the besieged Gaza, in what was the first time it broke its silence on the bloody war.

According to diplomatic sources, Security Council members are working on a new draft resolution focused on humanitarian aid.

But US Ambassador to the UN Robert Wood said that he didn't think a Security Council resolution "would be useful at this point."

"A lot of the good work that has been going on trying to improve the situation has been happening on the ground in the region, and we need to continue that."

Israel has killed at least 16,248 Palestinians and wounded more than 43,616 others in relentless air and ground attacks on the enclave since October 7.

The Israeli death toll stands at 1,200, which was revised down from 1,400.