Israeli Prime Minister Benjamin Netanyahu called genocide allegations over Gaza 'the biggest lie of the century' at the UN General Assembly in New York on Thursday, days after Mayor Zohran Mamdani described him as an 'architect' of genocide. Scores of delegates walked out before Netanyahu spoke.

The address followed Mamdani's renewed call for federal authorities to arrest Netanyahu under an International Criminal Court warrant, which the mayor says New York cannot enforce. In an interview with CNN, Mamdani called Netanyahu 'an architect of a horrific genocide of the Palestinian people'. Israel rejects the genocide allegation.

The Palestinian Mission to the UN had asked other delegations to bring staff to the assembly hall and leave together when Netanyahu was announced. It said the departure would signal opposition to what it called Israel's genocide, war crimes and illegal occupation. Israel disputes those accusations.

Cheers and boos accompanied Netanyahu's arrival at the rostrum. With many seats empty after delegates left, General Assembly President Khalilur Rahman repeatedly called for order. Netanyahu called those who walked out 'moral cowards' and challenged anyone still planning to leave to do so.

He also defended Israel's attack on Iran, calling the decision 'one of the easiest decisions I've ever had to make'. Netanyahu thanked US President Donald Trump for acting against Iran and claimed that leaders of some countries whose delegates had left the hall privately thanked Israel. He insisted Israel would continue to win because it had no other choice.

Mamdani has described Netanyahu as a 'war criminal' and urged federal authorities to act on the International Criminal Court warrant. He has acknowledged that New York City cannot execute it. The distinction matters in the city hosting Netanyahu's speech. The mayor can demand action, but has said the power to make an arrest does not lie with him.

Netanyahu's rejection of the genocide charge came after several world leaders accused Israel of genocide and war crimes during the UN gathering. The war began with the Hamas-led attack on Israel on 7 October 2023, in which about 1,200 people were killed and 251 taken hostage.

The Gaza Health Ministry says at least 73,928 Palestinians have been killed in Israel's subsequent offensive.

A ceasefire agreed last October halted the heaviest fighting and brought the release of the remaining hostages. Further steps have stalled. Israel still controls most of Gaza and carries out strikes near areas held by its military, while Hamas has neither disarmed nor relinquished power. Reconstruction has yet to advance in the devastated territory.

Earlier on Thursday, Palestinian President Mahmoud Abbas addressed the assembly by prerecorded video from Ramallah after the United States denied him a visa.

He urged countries that have criticised the war to take concrete steps, asking how long some would remain silent or continue supplying Israel with weapons.

Abbas pressed for a two-state solution and said Palestinians could live alongside Israel. He also insisted that Gaza, the West Bank and east Jerusalem should eventually be governed together.

Netanyahu has said a Palestinian state will not be established while he leads Israel and argues that the Palestinian Authority is not a peace partner. When Abbas spoke, the Israeli delegation's seats were empty.