Israel hosted an event at the United Nations on Monday to mark one year since the Hamas massacre, vowing to fight until all hostages held in Gaza by the Palestinian terrorists are freed and assailing the world body for failing to condemn the massacre.

"The U.N. has failed in its most basic mandate to protect the innocent and condemn evil. The resolutions that the U.N. did pass were about the situation in Gaza," said Israel's U.N. Ambassador Danny Danon, referring to action taken by the 15-member Security Council and the 193-member General Assembly.

During the shock Hamas rampage a year ago some 1,200 people were killed and about 250 taken hostage. More than 100 hostages remain held in Gaza by Hamas.

Israel's ally the United States vetoed a draft Security Council resolution on Oct. 18, 2023, that would have condemned Hamas and urged Gaza aid access. The U.S. had argued it needed more time to broker humanitarian access and was disappointed the text did not mention Israel's right to self-defense.

"There are those in the Security Council, and outside, who fail to condemn Hamas' atrocities or even say the word Hamas," U.S. Ambassador to the U.N. Linda Thomas-Greenfield told the Oct. 7 commemorative event on Monday.

"There are those in the region who have sought to build on Hamas' actions and are now pushing the Middle East to the precipice of a broader war — terrorist groups like the Houthis and Hezbollah," she said, also accusing Iran of seeking to take advantage of the situation to advance a "destructive agenda."

The Hamas attack triggered Israel's retaliation in Gaza, sparking a humanitarian crisis in the besieged enclave where authorities of Hamas say more than 41,000 people have been killed. The conflict has raised fears of all-out regional war, pitting Israel against Iran and the militant groups that it backs.

In recent weeks Israel killed the leader of Lebanon's Hezbollah and began a ground assault against the Iran-backed terrorist group. Iran then attacked Israel in a missile strike.

When asked earlier on Monday if Israel had made a decision on how to respond to Iran's attack, Danon told reporters: "We are debating it. The cabinet met and will continue to meet. We will choose the exact location and the way of the response."

Amid animosity between Israel's government and Secretary-General Antonio Guterres — who was barred last week by Israel's foreign minister from entering the country — U.N. spokesperson Stephane Dujarric said he did not believe any U.N. officials had been invited to Israel's event at U.N. headquarters.

In a video released over the weekend to mark the first anniversary of the Hamas attacks on Israel, Guterres said: "This is a day for the global community to repeat in the loudest voice our utter condemnation of the abhorrent acts of Hamas, including the taking of hostages."