I'm not telling you what I'm doing: Donald Trump on Iran nuclear deal

Earlier, Netanyahu said his govt had captured tens of thousands of documents proving Iran pursued nuclear weapons while it told the world it only sought civilian nuclear power

US President Donald Trump has said he will decide on whether to withdraw from the deal within 12 days after Israeli Prime Minister Benjamin Netanyahu claimed Iran covered up a secret nuclear weapons programme.

Netanyahu on Monday said he has proof about Iran's "secret nuclear weapons programme". The Israeli Prime Minister gave Trump "plenty of ammunition for pulling out of the 2015 pact" on Monday, CBS News reported.

Under the deal, Iran agreed to stop its nuclear programme in return for sanctions being lifted. But Netanyahu insists Iran didn't live up to its end of the bargain.

"I'm here to tell you one thing: Iran lied. Big time," Netanyahu said.

Unveiling bookshelves full of binders, Netanyahu said his government had captured tens of thousands of documents proving Iran pursued nuclear weapons while it told the world it only sought civilian nuclear power.

"Incriminating charts, incriminating presentations, incriminating blueprints, incriminating videos and more," he said.

Netanyahu said the material was taken from a secret government facility he called Iran's "atomic archive."

"Even after the deal, Iran continued to preserve and expand its nuclear weapons know-how for future use. Why would a terrorist regime hide and catalogue its files if not to use them at a later date?" Netanyahu asked.

On Monday evening, the White House issued a statement saying Netanyahu's information is "new and compelling."

"This information provides new and compelling details about Iran's efforts to develop missile-deliverable nuclear weapons," the statement read. "These facts are consistent with what the United States has long known: Iran has a robust, clandestine nuclear weapons program that it has tried and failed to hide from the world and from its own people."

The statement ended with: "The Iranian regime has shown it will use destructive weapons against its neighbours and others. Iran must never have nuclear weapons."

Netanyahu's speech comes ahead of a May 12 deadline for Trump to decide whether the US will stay in the Barack Obama-era nuclear deal. The agreement called for international inspections of its nuclear facilities.

At the White House, Trump said he was keeping his options open.

"I'm not telling you what I'm doing, but a lot of people think they know," Mr Trump said. "And on or before the 12th, we'll make a decision."

Informed sources said the Israelis shared their intelligence with the US before Monday's press conference. Trump said it proved the agreement was a bad deal.

"And I've been saying that it is happening. They're not sitting back idly... they're setting off missiles which they say are for television purposes. I don't think so," Trump said.

The president's new Secretary of State Mike Pompeo mentioned Iran at his confirmation hearing earlier this month.

"With the information, I have been provided, I have seen no evidence they are not in compliance today," Pompeo said.