Reading a statement outside the Security Council chambers at United Nations headquarters in New York, Mr. Guterres criticized “any unilateral measures that would jeopardize the prospect of peace for Israelis and Palestinians,” underscoring the administration’s departure from decades of American policy.

“Jerusalem is a final-status issue that must be resolved through direct negotiations between the two parties on the basis of the relevant Security Council and General Assembly resolutions, taking into account the legitimate concerns of both the Palestinian and the Israeli sides,” Mr. Guterres said.

“In this moment of great anxiety, I want to make it clear: There is no alternative to the two-state solution,” he said. “There is no Plan B.”

In Rome, Pope Francis prayed that Jerusalem’s status be preserved and needless conflict avoided.

“I cannot remain silent about my deep concern for the situation that has developed in recent days,” Francis said at his weekly general audience at the Vatican. “And at the same time, I wish to make a heartfelt appeal to ensure that everyone is committed to respecting the status quo of the city, in accordance with the relevant resolutions of the United Nations.”

“Jerusalem is a unique city,” he said, “sacred to Jews, Christians and Muslims, where the Holy Places for the respective religions are venerated, and it has a special vocation to peace.”