Tel Aviv, Feb 15 (DPA) Washington's top military officer was in Israel Monday to discuss action against Iran's nuclear programme, amid heightened coordination on the issue which was also likely to see US Vice President Joe Biden visit Jerusalem.

Admiral Michael Mullen, the chairman of the Joint Chiefs of Staff, was holding meetings with senior commanders of the Israel Defence Forces (IDF) General Staff.

In a message to Israel's decision-makers late Sunday, Mullen warned against the 'unintended consequences' that a military strike against Iran could trigger.

He nonetheless stressed that the option of such a military strike remained on the table, but that diplomacy should be exhausted first.

'I'm still hopeful that diplomacy and sanctions and dialogue will achieve results,' he told a news conference in Tel Aviv.

'My president has been very clear that from a policy standpoint, you know, Iran cannot have a nuclear weapon, nuclear capability,' he said.

Asked when in his estimation Iran would achieve the know-how to build an atom bomb, he replied: 'I wouldn't pick a specific date. The window ... that we talk about is somewhere between one to three years.'

The official guest of his Israeli counterpart, Lieutenant-General Gabi Ashkenazi, Mullen was scheduled to pay his respects to the victims of the Nazi genocide of the Jews by visiting Jerusalem's Yad Vashem Holocaust memorial institute Monday afternoon.

Biden, meanwhile, was expected to also visit Israel within a month, Israeli media reported, quoting Israeli government officials.

It would be Biden's first visit since the administration of US President Barack Obama took office one year ago.

Obama himself has thus far refrained from visiting Israel, as peace talks with the Palestinians remain suspended.