Israel has unveiled "half ton" of Iranian nuclear documents which it claims prove that Tehran covered up a nuclear weapons programme before signing a deal with the international community in 2015.
In a speech delivered in English and relying on his trademark use of visual aids, prime minister Benjamin Netanyahu claimed that the material showed Iran cannot be trusted, and urged President Donald Trump to withdraw from the deal next month.
"Iran lied, big time," Mr Netanyahu said.
His presentation, delivered on live TV from Israeli military headquarters in Tel Aviv, was his latest attempt to sway international opinion on the nuclear deal.
The agreement offered Iran relief from crippling sanctions in exchange for curbs on its nuclear programme.
Mr Netanyahu furiously fought the deal while Barack Obama was negotiating it, and he has been a leading critic since it was signed. He says it does not provide sufficient safeguards to prevent Iran from reaching a nuclear weapons capability.
He has found a welcome partner in Mr Trump, who has called the agreement "the worst deal ever".
The US president has signalled he will pull out of the agreement by May 12 unless it is revised, but he faces intense pressure from European allies not to do so.
Mr Netanyahu said he would share the newly uncovered information with Western allies and the international nuclear agency.
Iran has adamantly denied ever seeking nuclear weapons. The semi-official Fars news agency, believed to be close to the hard-line Revolutionary Guard, dismissed Mr Netanyahu's speech as a "propaganda show".
The PM said Israel had obtained 55,000 pages of documents and 183 CDs of secret information from an Iranian nuclear weapons programme called Project Amad.
He said the material was gathered from a vaulted Iranian facility a few weeks ago "in a great intelligence achievement".
He began his presentation with a series of video clips of Iranian leaders saying their country never pursued nuclear weapons.
He provided no direct evidence that Tehran has violated the 2015 deal. The agreement is not believed to have banned Iran from keeping its old records.
But Mr Netanyahu said the existence of the documents proves that Tehran is waiting to resume its race to build a bomb.
"We can now prove that Project Amad was a comprehensive programme to design, build and test nuclear weapons," he said.
"We can also prove that Iran is secretly storing Project Amad material to use at a time of its choice to develop nuclear weapons."
He and Mr Trump say the deal should address Iranian support for militants across the region and Iran's development of long-range ballistic missiles, as well as eliminate provisions that expire over the next decade.
Ahead of Mr Netanyahu's presentation, Iran's foreign minister, Mohammad Javad Zarif, mocked the Israeli leader by tweeting a photo of his famous 2012 UN speech in which he used a cartoon-like drawing of a bomb to rail against Iran's nuclear programme.
"The boy who can't stop crying wolf is at it again," Mr Zarif said. "Undeterred by cartoon fiasco at UNGA. You can only fool some of the people so many times."