But while Netanyahu accused Israel's main enemy Iran of lying about its nuclear ambitions, he did not provide evidence that it had actively worked to obtain an atomic weapon since the 2015 agreement between Tehran and six world powers.

Iran has always denied it sought a nuclear weapon, insisting its atomic programme was for civilian purposes.

Netanyahu made the comments in an elaborate presentation that included props, video and slides, broadcast live on television from Tel Aviv.

He said Israel had obtained tens of thousands of files "a few weeks ago in a great intelligence achievement," saying they had been moved to a secret compound in Tehran in 2017 that looked dilapidated from the outside.

The material obtained weighed a half a tonne, he said.

As he spoke, binders that he said held copies of original documents were on shelves behind him, as were cases containing CDs.

"Tonight we're going to reveal new and conclusive proof of the secret nuclear weapons programme that Iran has been hiding for years from the international community in its secret atomic archive," Netanyahu said.

"We're going to show you Iran's secret nuclear files."

He then laid out what he said was a years-old secret nuclear weapons programme stored away and which could be put into action at any time.

The details have been shared with the United States and will also be given to other countries and the International Atomic Energy Agency (IAEA), he said.

- 'Boy who cries wolf' -

After Netanyahu's statement was announced but before he spoke, Iranian Foreign Minister Mohammad Javad Zarif already dismissed it.

"The boy who can't stop crying wolf is at it again," he wrote on Twitter. "You can only fool some of the people so many times."

Zarif then took to twitter again to lambast both Netanyahu and US President Donald Trump, who has a May 12 deadline to decide on whether or not to walk away from the nuclear deal.

Trump "is jumping on a rehash of old allegations already dealt with by the IAEA to 'nix' the (2015 nuclear) deal", Zarif tweeted.

"How convenient. Coordinated timing of alleged intelligence revelations by the boy who cries wolf just days before May 12," he added.

Trump has derided the nuclear deal with Iran as "insane" partly because its restrictions on Iran's nuclear activities begin expiring in 2025.

Most world powers however say the nuclear deal is working as intended for now and is the best way to keep Iran from acquiring the bomb.

French President Emmanuel Macron and Chancellor Angela Merkel of Germany left Washington last week after talks with Trump which failed to secure any promise to keep the deal alive.

- 'Dominate the Middle East' -

The Israeli premier has repeatedly called for the accord -- which Iran signed with Britain, France, China, Russia, the United States and Germany -- to either be altered or scrapped.

He says the agreement does not prevent Tehran from eventually obtaining nuclear weapons and says the lifting of sanctions has increased Tehran's ability to finance proxy militants in the Middle East.

Netanyahu also wants to see curbs on Iran's missile programme.

On Monday, he said the nuclear deal was "based on Iranian lies and Iranian deception."

"Even after the deal, Iran continued to preserve and expand its nuclear weapons know-how for future use," Netanyahu said.

His presentation came after he met visiting US Secretary of State Mike Pompeo on Sunday and spoke with Trump by phone on Saturday.

Pompeo reiterated during the visit that Trump will withdraw from the nuclear deal "if we can't fix it".

Trump and his Middle East allies argue the deal, approved by Barack Obama, was too weak and needs to be replaced with a more permanent arrangement and supplemented by controls on Iran's missile programme.

Pompeo, a former CIA chief and congressman, also joined Netanyahu in lashing out at Iran on Sunday.

"Iran's ambition to dominate the Middle East remains," Pompeo said.

Rob Malley, a former official in Obama's administration, said on Twitter that "for those who have followed the Iranian nuclear file, there is nothing new in (Netanyahu's) presentation".

"All it does is vindicate need for the nuclear deal. But the Israeli prime minister has an audience of one: Trump. And he's unfortunately unlikely to reach the same conclusion."

Israel is considered the Middle East's sole nuclear-armed nation, though it has never acknowledged the capability.