Israeli Prime Minister Benjamin Netanyahu on Monday claimed the country has evidence of a "secret" Iranian nuclear weapons programme, as US President Donald Trump decides whether or not to pull out of the deal next month.
"After signing the nuclear deal in 2015, Iran intensified its efforts to hide its secret files," he said. "In 2017 Iran moved its nuclear weapons files to a highly secret location in Tehran."
Mr Netanyahu, standing in front of a large LED screen, said Israel, in an intelligence coup, had covertly obtained 55,000 records and 55,000 files stored on 183 CDs relating to an Iranian bid to secretly pursue nuclear weapons activity.
He said the cache represented "half a ton" of Iranian documents, which he called the "atomic archive", which showed the nuclear deal agreed between Tehran and world powers in 2015 was "based on lies".
He said the documents about what he said was named Iran's 'Project Amad' provided "new and conclusive proof" that the Iranian regime has been hiding a nuclear weapons development programme it had vowed to give up almost three years earlier.
"Iran lied, big time. After signing the nuclear deal, Iran intensified its efforts to conceal its nuclear weapons files", he said.
"Iran lied about never having a nuclear weapons program", he continued. "Even after the deal, Iran continued to preserve and expand its nuclear weapons knowhow for future use."
It came as US President Donald Trump mulls whether to pull out of the deal that he has long condemned as one of the worst agreements "in history".
Mr Netanyahu's speech came after a trip to Israel by newly-appointed Secretary of State Mike Pompeo, who held talks with the Israeli leader about the Iranian nuclear deal.
His presentation included videos that purported to show a nuclear weapons development facility.
Mr Netanyahu said the US government could vouch for its authenticity, and that the material would be shared with the International Atomic Energy Agency, the global nuclear watchdog, and other governments.
The surprise announcement took place at the Israeli military headquarters in Tel Aviv. Mr Netanyahu cancelled a parliamentary speech and held an emergency security cabinet meeting before he spoke.
Israel and Iran are archenemies and Mr Netanyahu has been a longtime critic of the nuclear agreement signed in July 2015. That deal sought to rein in Tehran's uranium enrichment in return for the lifting of crippling international sanctions on the Iranian economy.
Trump has repeatedly threatened to rip up the agreement, saying that it handed back hundreds of millions to Iran in unfrozen assets that it could use to finance terrorism across the Middle East.
Iran is widely accused of sponsoring proxy groups such as Hezbollah in Lebanon, the Houthi rebels in Yemen and Palestinian militant group Hamas in Gaza.