Secretary of State Antony Blinken delivered a forceful defense of Israel’s military actions at the United Nations Security Council, but Blinken said "humanitarian pauses must be considered" to protect civilians in Gaza -- the administration’s strongest statement of a support for any type of halt in Israel’s efforts to vanquish Hamas.

"We must affirm the right of any nation to defend itself and to prevent such heart from repeating itself. No member of this council, no nation in this entire body. could or would tolerate the slaughter of its people," Blinken said.

The secretary said every member of the U.N. has a "responsibility to denounce the member states that arm, fund and train Hamas or any other terrorist group that carries out such horrific acts,” reminding them that many other foreign nationals were also killed and kidnapped in its attacks."

Blinken then turned to ongoing efforts to protect civilian lives, first emphasizing that Hamas is responsible for putting the innocent in harm’s way, before shifting to Israel’s responsibilities.

“Hamas must cease using them as human shields,” he said. “Israel must take all possible precautions to avoid harm to civilians. It means means food, medicine and water and other assistance must flow into Gaza and to the areas people need them. It means civilians must be able to get out of harm's way. It means humanitarian pauses must be considered for these purposes.”

Previously, the State Department and other U.S. officials flatly rejected calls for any kind of ceasefir, arguing, as State Department spokesperson Matt Miller did Monday, that it would “give Hamas the ability to rest, to refit and to get ready to continue watching terrorist attacks against Israel.”

In his remarks, Blinken also detailed the administration’s efforts to prevent the conflict from spreading in the Middle East, but emphasized the threat posed by Iran and promised the U.S. would not allow attacks on Americans to go unanswered.

“We do not want this war to widen, but if Iran or its proxies attack U.S. personnel anywhere, make no mistake -- we will defend our people, we will defend our security -- swiftly and decisively,” he vowed.

-ABC News' Shannon Crawford

Israel's ambassador to the United Nations, Gilad Erdan, is calling on U.N. Secretary-General António Guterres to resign, saying he's "completely disconnected from the reality in our region."

At the United Nations Security Council meeting, Gutteres delivered some of most forceful rhetoric on the Israel-Hamas war to date, demanding an immediate humanitarian ceasefire “to ease epic suffering, make the delivery of aid easier and safer and facilitate the release of hostages.”

The Secretary-General’s speech, especially his assertion that “the attacks by Hamas did not happen in a vacuum," sparked immediate backlash from Erdan.

"The shocking speech by the UN Secretary-General at the Security Council meeting, while rockets are being fired at all of Israel, proved conclusively, beyond any doubt, that the Secretary-General is completely disconnected from the reality in our region and that he views the massacre committed by Nazi Hamas terrorists in a distorted and immoral manner," Erdan said. "His statement that, 'The attacks by Hamas did not happen in a vacuum,' expressed an understanding for terrorism and murder."

"It’s truly sad that the head of an organization that arose after the Holocaust holds such horrible views," Erdan said.

"There is no justification or point in talking to those who show compassion for the most terrible atrocities committed against the citizens of Israel and the Jewish people," Erdan said.

Guterres' spokesperson, Stephane Dujarric, told ABC News, "The Secretary said what he said. Spokesman is not responding further."

-ABC News' Shannon Crawford

The Israeli police said they've identified at least 784 people killed by Hamas.

Police said some bodies were in such bad condition that they have not yet been identified.

At least 1,400 people have died and 4,629 others have been injured in Israel since Hamas' Oct. 7 attack, according to Israeli authorities.

The Biden administration has sent Lt. Gen. James Glynn, a three-star Marine general who is currently serving as the head of Marine personnel, to Israel to advise the country on its military operations, according to a U.S. official.

The news was first reported by Axios on Monday.

Glynn is "not directing operations" but rather is "purely there to provide military advice and pose hard questions to help [the Israel Defense Forces] think through various scenarios," the U.S. official told ABC News.

The official said Glynn was in Israel "temporarily" and was not expected to still be there when a ground operation starts.

-ABC News' Ben Gittleson