US Vice President Joe Biden said in a television interview that the United States would not stand in the way of Israel in its dealings with Iran's nuclear ambitions.

"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," Biden told ABC television's "This Week" Sunday.

"Whether we agree or not. They're entitled to do that... We cannot dictate to another sovereign nation what they can and cannot do when they make a determination, if they make a determination, that they're existentially threatened. "

But the top US military officer meanwhile warned of the dangers posed by any military strike against Iran.

"It could be very destabilising, and it is the unintended consequences of that which aren't predictable," Admiral Mike Mullen, the chairman of the US Joint Chiefs of Staff told "Fox News Sunday."

However, he added: "I think it's very

important, as we deal with Iran, that we don't take any options, including military options, off the table. "

A senior Iranian official visiting Japan said Monday his country would respond "in a very full-scale and very decisive way" ifit were attacked by Israel.

"I think that America and Israel are fully aware what kind of result such a wrong judgement will entail," Alaeddin Boroujerdi, chairman of the Iranian Parliament's National Security and Foreign Policy Commission, said in Tokyo.

"Israel showed its military power sufficiently in the 22-day war," its offensive in Gaza early this year, he told reporters.

"That kind of erroneous judgement posesa threat to the entire Middle Eastern region and the world."

He added: "If (an Israeli attack) occurred, then the Islamic Republic of Iran will respond in a very full-scale and very decisive way."

President Barack Obama has said he wants to see progress on his diplomatic outreach to Iran by year's end, while not

excluding a "range of steps," including tougher sanctions, if Tehran continued its controversial nuclear drive.

Hawkish Israeli Prime Minister Benjamin Netanyahu has not ruled out a possible military strike against Iran, insisting that Tehran, which the Mossad spy agency could have a ready-to-launch nuclear bomb within five years, must not obtain nuclear weapons.

"If the Netanyahu government decides to take a course of action different than the one being pursued now, that is their sovereign right to do that. That is not our choice," Biden said. "But there is no pressure from any nation that's going to alter our behaviour as to how to proceed.”

farad* the region's sole if undeclared nuclear-armed state, contends - as does the West - - that Iran is seeking to acquire a nuclear arsenal, despite Tehran's repeated denials.

The Jewish state has also called the Islamic Republic a threat to its existence, citing Iranian President Mahmoud Ahmadinejad's call to wipe Israel off the map.