Israel has uncovered 55,000 files of "incriminating" information on the Iranian nuclear program, Israeli Prime Minister Benjamin Netanyahu announced late Monday.
Iran has moved its nuclear weapons program to a secret location, the prime minister said in a surprise announcement.
"Warehouse contained Iran's secret atomic archives locked in massive safes," Netanyahu said, adding that "Iran lied" after signing the nuclear deal.
"Israel can reveal new and conclusive proof that Iran has been hiding nuclear weapons activity."
Before the announcement, Netanyahu canceled a speech at Parliament and convened an emergency meeting of his security cabinet at the Israeli military headquarters in Tel Aviv.
U.S. President Donald Trump has praised Netanyahu's presentation, saying the presentation and other recent events show that he has been "100 percent right" about Iran.
He said he watched part of Netanyahu's presentation and that it was "good" and Iran's behavior is "just not an acceptable situation." He pointed to missile tests, saying Iran is "not sitting back idly."
Trump has declined to say whether he will withdraw the U.S. from the 2015 nuclear deal, saying the U.S. "got nothing" for the sanctions relief granted Iran under the accord.
Netanyahu's planned statement came on the heels of a missile attack in northern Syria that killed at least 26 pro-regime fighters, mostly Iranians, according to a Syria war monitoring group. Israel had no comment on the strike, but there was widespread speculation that Israel was behind it.
Israel and Iran are archenemies, and Israel has repeatedly said it would not allow Iran to establish a permanent military presence in Syria. Iran, which supports Syria's Bashar Assad, has accused Israel of carrying out another airstrike in Syria earlier this month that killed seven Iranian military advisers, and has vowed revenge.
Overnight Monday, Netanyahu talked to U.S. President Donald Trump on the phone. The White House said the two leaders discussed the continuing threats and challenges facing the Middle East, "especially the problems posed by the Iranian regime's destabilizing activities."
U.S. Secretary of State Mike Pompeo on Sunday ratcheted up the Trump administration's rhetoric against Iran and offered support to Israel and Saudi Arabia in their standoff with Tehran.
"The United States is with Israel in this fight," Pompeo said.
The 2015 nuclear deal gave Iran relief from crippling sanctions in exchange for curbs on its nuclear program.
Netanyahu has been a leading critic of the agreement, saying it fails to prevent Iran from gaining nuclear weapons capability and welcoming Trump's pledges to withdraw from the deal if it is not changed.
Both Trump and Netanyahu 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.
Trump has set a May 12 deadline to decide whether to pull out of the Iran deal — something he appears likely to do despite heavy pressure to stay in from European allies and other parties.
Iran's foreign minister, Mohammad Javad Zarif, mocked the Israeli leader by tweeting out a photo of Netanyahu's famous 2012 U.N. speech in which he used a cartoon-like drawing of a bomb to rail against Iran's nuclear program.
"The boy who can't stop crying wolf is at it again," Zarif said. "Undeterred by cartoon fiasco at UNGA. You can only fool some of the people so many times."
Tehran has sent thousands of allied fighters to back Assad's forces in Syria's seven-year civil war.
On Monday, Iran's Supreme Leader Ayatollah Ali Khamenei said the time when Iran's enemies can "hit and run" is over.
"They know if they enter military conflict with Iran, they will be hit multiple times," he said, according to his website. He did not specifically refer to the latest attack in Syria.
Michael Oren, a senior Israeli official, had no comment on the airstrike in Syria, but warned both Syria and Iran against trying to attack.
"If someone shoots at us, we shoot back and we will shoot back either at the Syrian army or the Iranians, at the origin of the aggression," Oren told foreign reporters.
He also said Israel would continue to enforce its "red lines" in Syria, including preventing Iran from transferring guided missiles to Hezbollah or building military bases in Syria.
"If that leads to an escalation, the escalation will be on the head of Iran and not the state of Israel," he said. "We have to defend ourselves."
