The United Nations (UN) secretary-general Antonio Guterres has invoked Article 99 of the UN Charter, urging the UN Security Council to act on the war in Gaza.

The rare move by the secretary-general comes as the Security Council is yet to adopt a resolution calling for a ceasefire between Israel, Hamas and their allies.

Considered the UN’s most powerful body, the 15-member Security Council is tasked with maintaining international peace and security.

In his letter to the council’s president, Guterres invoked this responsibility, saying he believed the situation in Israel and the occupied Palestinian territories, “may aggravate existing threats to the maintenance of international peace and security”.

Guterres – who has been calling for an “immediate humanitarian ceasefire” since October 18 – also described “appalling human suffering, physical destruction and collective trauma across Israel and the occupied Palestinian territories”.

In response to Guterres’s letter, Security Council member the United Arab Emirates posted on X to say it had submitted a new draft resolution to the council, and “called for a humanitarian ceasefire resolution to be adopted urgently”.If the council does choose to act on Guterres’s advice and adopt a ceasefire resolution, it does have additional powers at its disposal to ensure the resolution is implemented, including the power to impose sanctions or authorise the deployment of an international force.

But the council’s five permanent members – China, Russia, the US, the UK and France – hold veto power.

The US used that veto on October 18 against a resolution that would have condemned Hamas’s attack on Israel while calling for a pause in the fighting to allow humanitarian assistance into Gaza.

Twelve other council members voted in favour, while Russia and the UK abstained.

Guterres said the Security Council’s continued lack of action and the sharp deterioration of the situation in Gaza had compelled him to invoke Article 99 for the first time since he took on the top job at the UN in 2017.

He warned public order in Gaza could soon break down amid the complete collapse of the humanitarian system.

“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,” he wrote.“Such an outcome must be avoided at all costs.”But Guterres’s invocation of Article 99 was not welcomed by Israel’s ambassador to the UN, Gilad Erdan.

In a post on X, Erdan described the letter as “more proof” of Guterres’s “moral distortion and his bias against Israel”.

“The secretary-general’s call for a ceasefire is actually a call to keep Hamas’s reign of terror in Gaza,” said Erdan, who also repeated his call for Guterres to resign.

The UN Charter only provides limited powers to the UN secretary-general, who serves as the UN’s Chief Administrative Officer and is elected by member states.

Article 99 of the UN Charter gives the secretary-general the power to “bring to the attention of the Security Council any matter which in his opinion may threaten the maintenance of international peace and security”.

“The fact that this tool has not been used since 1989 does resonate diplomatically and symbolically here in New York,” Daniel Forti, a senior analyst on UN advocacy and research at the International Crisis Group, told Al Jazeera.

But Forti added that it will not “fundamentally change the political calculation of the Security Council’s most powerful members”.