Israeli Prime Minister Ehud Olmert has said Iran's nuclear programme must be stopped by "all possible means".
Speaking during a visit to Washington, he said Tehran must be made to see it would suffer devastating repercussions if it pursued atomic weapons, BBC reported.
The US and others have accused Iran of building a nuclear arms capability. Tehran says its programme is peaceful.
Mr Olmert's US visit comes as he faces pressure at home over corruption allegations, which he denies.
"The Iranian threat must be stopped by all possible means," Mr Olmert said in his speech before the American Israel Public Affairs Committee - a lobby group.
"The international community has a duty and responsibility to clarify to Iran, through drastic measures, that the repercussions of their continued pursuit of nuclear weapons will be devastating," he added.
Mr Olmert is expected to discuss the issue in talks with President George W Bush on Wednesday.