Joe Biden has just returned from a visit to the Middle East
US Vice-President Joe Biden has hinted the administration will not restrain Israel if it decides on military action to remove any Iranian nuclear threat.
Mr Biden told ABC television the US could not "dictate to another sovereign nation what they can and cannot do".
Mr Biden also said President Obama's offer of dialogue with Iran remained on the table.
A senior Iranian official said his country would respond decisively to any attack by Israel on its facilities.
Mr Obama has given Iran until the end of the year to talk about its nuclear programme, which Iran insists is for energy purposes only.
Western countries are concerned Tehran is working to acquire a nuclear weapons capability.
Israeli Prime Minister Benjamin Netanyahu has indicated Israel would take matters into its own hands if Iran did not show a willingness to negotiate.
Appearing on ABC's current affairs programme This Week, host George Stephanopoulos asked Mr Biden whether the Israeli position was the right approach.
The vice-president replied: "Israel can determine for itself - it's a sovereign nation - what's in their interest and what they decide to do relative to Iran and anyone else."
He added that this was the case, "whether we agree or not" with the Israeli view.
Asked whether the US would stand in the way if the Israelis decided to launch a military attack against Iranian nuclear facilities, Mr Biden said Israel, like the US, had a right to "determine what is in its interests".
White House spokesman Tommy Vietor said Mr Biden was not signalling any change of approach on Iran or Israel.
"The vice-president refused to engage [in] hypotheticals, and he made clear that our policy has not changed," he was quoted as saying by the Associated Press news agency.
Alaeddin Boroujerdi, chairman of the Iranian parliament's national security and foreign policy commission, responded to Mr Biden's remarks while on a visit to Tokyo.
Iran would respond "in a very full-scale and very decisive way" to an Israeli attack, he said.
"I think that America and Israel are fully aware what kind of result such a wrong judgement will entail," he said in remarks quoted by AFP news agency.
"Israel showed its military power sufficiently in the 22-day war [in Gaza]. That kind of erroneous judgement poses a threat to the entire Middle Eastern region and the world."