Trump has threatened to tear up the 2015 agreement that lifted sanctions on Iran in exchange for curbs to its nuclear activity, unless it curbs its ballistic missile programme by May 12.

"Israel will not allow regimes that seek our annihilation to acquire nuclear weapons," Netanyahu told an audience of diplomats in a speech in Jerusalem.

"This is why this deal has to be either fully fixed or fully nixed," he said in English.

Iran says it is ready to relaunch its nuclear programme -- which the West suspects is designed to produce a bomb -- if Trump kills the deal.

Netanyahu said the 2015 agreement leaves Iran able to quickly reboot its nuclear programme to enable military production.

"It gives Iran a clear path to a nuclear arsenal," he said. "It allows, over a few years, unlimited enrichment of uranium, the core ingredient required to produce nuclear bombs."

The United States delivered much the same message Monday, at a meeting of the Nuclear Non-Proliferation Treaty (NPT) in Geneva.

Christopher Ford, US Assistant Secretary for International Security and Nonproliferation, said the Islamic republic's nuclear programme remained "dangerously close to rapid weaponisation".

Iran insists it never intended to build a nuclear weapon.