Israel is doing its part in confronting worldwide jihadist terrorism, though not all of its efforts are known to the public, Prime Minister Benjamin Netanyahu said Thursday, expressing Jerusalem’s full support for the American-led offensive against the Islamic State organization unveiled Wednesday.

In a major foreign policy address, Netanyahu warned of Iran acquiring nuclear weapons, saying this would cause the “ultimate terror.” Efforts to weaken Sunni terrorists should not result in strengthening Shiite radicalism, he urged.

The Islamic State, also known as IS and ISIS, is similar in ideology and strategy to Hamas, Hezbollah, al-Qaeda, Boko Haram, al-Shabab and other radical Islamist terrorist groups, Netanyahu said at a conference in Herzliya. “These groups must be fought. They must be rolled back and they must ultimately be defeated. That’s why Israel fully supports President [Barack] Obama’s call for united actions against ISIS.”

All civilized countries should stand together in the fight against the radical terrorism currently sweeping the Middle East, Netanyahu added. “And we are playing our part in this continued effort. Some of the things are known; some of the things are less known.”

The threat posed both by Sunni and Shiite radicalism has led “many Sunni Arab states” to reevaluate their relationship with Israel, he said. “They understand Israel is not their enemy but their ally in the fight against this common enemy. I believe that presents an opportunity for cooperation and perhaps an opportunity for peace.”

But the struggle against Sunni radicalism should not lead the world to neglect the threat of Shiite extremism, the prime minister warned, referring to proposals to have Iran support the global coalition against IS. “They’re two sides of the same coin. We don’t have to strengthen one to weaken the other. My policy is: Weaken both.”

The greatest threat to world peace, Netanyahu said, would be a nuclear-equipped Iran. “You would see things you never imagined could be possible,” he said, describing a scenario in which the regime succeeded in obtaining nuclear weapons. “Horrors you couldn’t even contemplate come to fruition. The ultimate terror. A terrorist regime with the weapons of the greatest terror of them all. We must not let that happen.”

Speaking at a conference organized by the International Institute for Counter-Terrorism, Netanyahu said all Islamist organizations terrorizing the Middle East are “branches of the same poisonous tree,” presenting a clear danger to the peace and security of the world. “It’s important not to let any of these groups succeed anywhere. Because if they gain ground somewhere, they gain ground everywhere. And their setbacks are also felt everywhere.”

‘We’ve seen this before: there’s a master race, now there’s a master faith’

These terror groups all operative according to the same tactics, the prime minister said. First they rain terror on their own people, and then on the rest of the world. “We’ve seen this before,” he said, and then made a reference to the Jewish people’s fate during World War II. “There’s a master race; now there’s a master faith. And that allows you to do anything to anyone, but first of all to your own people, and then to everyone else.”

Effectively confronting Islamist terrorism requires sophisticated weaponry, “but above all it requires, I believe, clarity and courage,” the prime minister said. “Clarity to understand: they’re wrong, we’re right. They’re evil, we’re good. No moral relativism there at all. These people who lop of heads, trample human rights into the dust, are evil. And they have to be resisted. Evil has to be resisted.”

Eventually, militant Islam will be defeated and disappear from the stage of history, Netanyahu added. “Because it’s a grand failure. It doesn’t know how to manage economies and it cannot offer to the young people to which it appeals any kind of future.” It may take a long time, but “I’m confident that militant Islam will perish. But we must not allow anyone to perish with it before it goes down,” he said. “That’s our task.”