Israeli prime minister Benjamin Netanyahu has warned that Hamas and the Islamic State group (IS) are "branches of the same poisonous tree," both bent on world domination through terror, just as the Nazis were.
In a blistering speech to the United Nations, Mr Netanyahu also hit back at Palestinian president Mahmoud Abbas, who accused Israel last week of carrying out war crimes and waging a "war of genocide" during the fighting in Gaza.
The Israeli leader said Hamas committed "the real war crimes" in Gaza by using Palestinian civilians as human shields.
Addressing the UN General Assembly's annual ministerial meeting, the Israeli leader argued that Israel's fight against Hamas and the US military campaign against the Islamic State are part of the same cause - the defeat of Islamic extremism.
Mr Netanyahu railed against world leaders for simultaneously condemning the Jewish state for its war with Hamas and praising president Barack Obama for attacking Islamic State militants and other extremists in Syria and Iraq.
"They evidently don't understand that (IS) and Hamas are branches of the same poisonous tree," the prime minister said.
He added that "when it comes to its ultimate goals", Hamas is IS, and IS is Hamas.
Mr Netanyahu said IS and Hamas, as well as other Muslim extremist movements, from al-Qaida and Nigeria's Boko Haram to Somalia's al-Shabab and Lebanon's Hezbollah, share the goal of imposing militant Islam on the world.
He likened them to "another fanatic ideology that swept into power eight decades ago" - Nazism.
To protect global peace and security, he said, "we must remove this cancer before it's too late".
Turning to another regional enemy, Mr Netanyahu warned that the gravest threat to the world today is the danger of Iran obtaining nuclear weapons. "It's one thing to confront militant Islamists on pickup trucks, armed with Kalashnikov rifles. It's another thing to confront militant Islamists armed with weapons of mass destruction," he said.
The Israeli leader added that Iranian president Hassan Rouhani's condemnation of the spread of terrorism last week amounted to "one of history's greatest displays of doubletalk".
He accused Iran itself of mounting terrorist attacks all around the world, and lumped the country in with Islamic extremist movements. "To say that Iran doesn't practice terrorism is like saying Derek Jeter never played shortstop for the New York Yankees," he said.
And Mr Netanyahu criticized the efforts of six world powers to reach a nuclear deal with Iran, saying: "To defeat (IS) and leave Iran as a threshold nuclear power is to win the battle and lose the war."
He also launched a scathing attack on the UN Human Rights Council, accusing it of continually singling out Israel for criticism when other parts of the world are awash in atrocities. He called the Human Rights Council's name "an oxymoron" and charged that the body has become "a terrorist rights council".
Mr Netanyahu said the council's treatment of Israel reflects "the return of one of the world's oldest prejudices."
"It's called anti-Semitism. It is now spreading in polite society, where it masquerades as legitimate criticism of Israel," he said.
Hanan Ashrawi, a member of the Palestine Liberation Organisation's executive committee, said Mr Netanyahu's speech was "a blatant manipulation of facts" aimed at misleading world leaders "through a combination of hate language, slander and argument of obfuscation".
In Washington, State Department spokeswoman Jen Psaki took issue with Netanyahu over the similarities between Hamas and Islamic State. She said that while the US considers both terrorist organisations, "we obviously believe that (Islamic State) poses a different threat to the United States".
Saeb Erekat, chief Palestinian negotiator, said Mr Netanyahu, in his remarks, "buried" the possibility of a two-state solution to the Arab-Israeli conflict based on the pre-war borders of 1967.
Mr Erekat also complained that Mr Netanyahu branded those who dare to stand up to Israel as anti-Semites.