United Nations Secretary-General Antonio Guterres on Wednesday invoked a rarely used article of the UN Charter calling on the Security Council to “press to avert a humanitarian catastrophe” in Gaza and unite in a call for a full humanitarian ceasefire between Israel and Hamas.

Article 99 of the founding UN Charter allows him to “bring to the attention of the Security Council any matter which in his opinion may threaten the maintenance of international peace and security.”

In a letter to the Council, Guterres said that more than eight weeks of fighting overall had “created appalling human suffering, physical destruction and collective trauma across Israel and the Occupied Palestinian Territory.”

“Hospitals have turned into battlegrounds”, he said, adding that amid the constant bombardment of all parts of Gaza and without shelter or the essentials to survive “I expect public order to completely break down soon.”

Guterres announced in a post on X that he invoked Article 99 for the first time in his tenure as the secretary general of the UN.

“Facing a severe risk of collapse of the humanitarian system in Gaza, I urge the Council to help avert a humanitarian catastrophe & appeal for a humanitarian ceasefire to be declared,” he wrote.

Meanwhile, around 900 people in Gaza were killed in Israeli airstrikes between Friday when a truce ended and Monday, according to Gaza’s Health Ministry, about the same number killed in strikes in Gaza over the four days following October 7.

Gaza’s health ministry, whose data the UN has deemed broadly reliable, on December 4 said that at least 15,899 Palestinians, 70% of them women or people under 18 whom it defines as children, have been killed in Israeli bombardments over eight weeks of warfare.