US Defence Secretary Leon Panetta arrived in Israel on Tuesday for talks to share information on Iran's nuclear programme, but said there would be no discussion about "potential attack plans."
Shortly after Panetta's arrival, Prime Minister Benjamin Netanyahu told private Channel 2 television Israel had not yet made any decision about a possible attack against Iran but reaffirmed his country's right to defend itself.
The Pentagon chief told a news conference in Cairo before flying to Jerusalem that "we have in the past and we'll continue to discuss the situation with regards to Iran and the threat that it poses in the region."
"I think it's the wrong characterisation to say that we're going to be discussing potential attack plans. What we are discussing are various contingencies on how we would respond," said Panetta.
Echoing the position held for months by the United States, the defence secretary said Washington was continuing to "work on a number of options in that area," although he did not specify.
Panetta said he plans to update Israel on "the situation with regards to Iran and the threat that it poses in the region" in talks with Netanyahu, President Shimon Peres and Defence Minister Ehud Barak.
On Sunday, Israeli daily Haaretz reported that US National Security Adviser Tom Donilon had recently briefed Netanyahu on contingency plans for a pre-emptive strike on Iran's nuclear facilities.
But an Israeli official, speaking on condition of anonymity, denied the report.
On Tuesday evening, Netanyahu said in response to a question during an interview with Channel 2: "I have not taken a decision" on any attack against Iranian nuclear facilities."
But the prime minister reaffirmed "the right of Israel to defend against any threat to its security and existence."
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"Israel's fate depends solely on us and no other country, however friendly," he said, in reference to the United States.
Asked about reports that the army, the Mossad intelligence agency and the Shin Bet internal security service were against any attack launched without US consent, he said: "In a democracy, only the political leaders decide, and the military executes."
He recalled that then premier Menachem Begin had given the green light in 1981 for an air strike against a nuclear plant in Iraq "despite the opposition at the time of the chiefs of the Mossad and military intelligence."
"Political leaders have a more global vision and it is they who bear supreme responsibility," Netanyahu said in another interview with private television Channel 10.
The Pentagon chief said on Monday that sanctions were having a "serious impact" on the Iranian economy, even if their results may not be immediately obvious.
Speaking in Tunisia at the start of a Middle East tour that will also take him to Jordan, he said: "What we all need to do is to continue the pressure economically and diplomatically."
Iran denies that its nuclear programme has any military dimesnion, insisting it is for civilian power generation and medical purposes only.
Israel is widely suspected to have the Middle East's sole if undeclared nuclear arsenal.
During his visit to Israel, Panetta will also discuss the situation in Syria and visit a battery of the "Iron Dome" missile defence system that protects the Jewish state from rockets fired by Islamist militants from Gaza and Lebanon.
The United States contributes to the financing of the Iron Dome system, and pledged another $70 million in May, having already provided $205 million to the project.
A major ally of Washington, Israel receives about $3 billion in US military aid each year.
By sending the Pentagon chief to Jerusalem, the administration of President Barack Obama also appears to be keen to send a message back home, as his trip comes just two days after White House hopeful Mitt Romney visited Israel.
On Friday, Obama signed a law reinforcing US security and military cooperation with Israel surrounded in the Oval Office by representatives of the pro-Israel lobby AIPAC.