UN Secretary-General Antonio Guterres said he regrets the Security Council's failure to demand a ceasefire in Gaza, condemning the divisions that have "paralysed" the world body.
Addressing Qatar's Doha Forum, Mr Guterres said the council was "paralysed by geostrategic divisions" that were undermining solutions to the Israel-Hamas war which started on 7 October.
The body's "authority and credibility were severely undermined" by its delayed response to the conflict, he said two days after a US veto prevented a resolution calling for a Gaza ceasefire.
"I reiterated my appeal for a humanitarian ceasefire to be declared," he told the forum.
"Regrettably, the Security Council failed to do it," he added.
"I can promise, I will not give up."
Mr Guterres had convened an emergency meeting of the UN Security Council after two months of fighting that have left more than 17,700 people dead in Gaza, most of them women and children, according to the territory's Hamas-run health ministry.
The secretary-general deployed the rarely-used Article 99 of the United Nations Charter to bring to the council's attention "any matter which in his opinion may threaten the maintenance of international peace and security".
The rule had not previously been invoked by a UN chief in decades.
"We are facing a severe risk of collapse of the humanitarian system," Mr Guterres told the Doha Forum.
"The situation is fast deteriorating into a catastrophe with potentially irreversible implications for Palestinians as a whole and for peace and security in the region."
The Israel-Hamas war was triggered by deadly attacks by Palestinian militant group Hamas on Israel.
The militants poured over the border into Israel on October 7, killing 1,200 people, mostly civilians, and kidnapping about 240 others, according to Israeli officials.
Mediation
Mediation efforts are continuing to secure a new Gaza ceasefire and free more hostages held by Hamas despite ongoing Israeli bombardment that is "narrowing the window" for a successful outcome, Qatar's prime minister said today.
"Our efforts as the state of Qatar along with our partners are continuing. We are not going to give up," Sheikh Mohammed bin Abdulrahman Al Thani told the Doha Forum, adding that "the continuation of the bombardment is just narrowing this window for us".
