US Secretary of State Mike Pompeo says a landmark nuclear deal with Iran was “built on lies”, after Israel claimed to have proof of a secret Iranian nuclear weapons programme.
Mr Pompeo said documents revealed by Israel’s prime minister were authentic.
Analysts say they show nothing new, highlighting that concerns over Iran’s nuclear ambitions led to the deal.
US President Donald Trump, who opposes the accord, has until 12 May to decide whether to abandon it or not.
Other Western powers, including signatories Britain and France, say Iran has been abiding by the deal and it should be kept.
Israeli Prime Minister Benjamin Netanyahu on Monday accused Iran of conducting a secret nuclear weapons programme, dubbed Project Amad, and said it had continued to pursue nuclear weapons knowledge after the project was shuttered in 2003.
That followed the revelation in 2002 by an exiled Iranian opposition group that Iran was constructing secret nuclear sites in breach of the nuclear Non-Proliferation Treaty, of which Iran was a signatory.
Mr Netanyahu presented what he said was evidence of thousands of “secret nuclear files” that showed Iran had lied about its nuclear ambitions before the landmark deal was signed in 2015.
Tension between the long-standing enemies has grown steadily since Iran built up its military presence in Syria, which lies to the north-east of Israel.