His letter to the council’s 15 members said Gaza’s humanitarian system was at risk of collapse after two months of war that has created “appalling human suffering, physical destruction and collective trauma,” and he demanded civilians be spared greater harm.

Guterres invoked Article 99 of the U.N. Charter, which says the secretary-general may inform the council of matters he believes threaten international peace and security.

U.N. spokesman Stephane Dujarric said he expects the secretary-general to address the Security Council on Gaza this week and to press for a humanitarian cease-fire.

It demands “an immediate humanitarian cease-fire” and expresses “grave concern over the catastrophic situation in the Gaza Strip and the suffering of the Palestinian civilian population.”

Mansour said a ministerial delegation from Arab nations and the 57-member Organization of Islamic Cooperation will be in Washington on Thursday to meet U.S. officials and press for an immediate cease-fire.

“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,” Guterres warned.

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