Prime Minister Benjamin Netanyahu reiterated on Thursday that Israel will not tolerate a nuclear-armed Iran, after returning from White House talks centred on Tehran's nuclear programme.
"We cannot accept that Iran has nuclear weapons because that would represent a danger to the existence of our country," the premier said in an interview on private Channel 10 television.
"We have the right, but also the duty to defend ourselves."
Western powers and Israel believe that Tehran's nuclear programme is aimed at acquiring an atomic bomb, but Iran insists its activities are peaceful.
Asked if he were prepared to let international sanctions against Iran work before attacking Iran, he replied: "I don't operate with a stop watch in my hand."
"We would be very happy if everything were resolved in a peaceful fashion, if Iran renounced its nuclear programme, dismantled its installations, especially in Qoms, and stopped enriching uranium," he said.
"If the sanctions work, all the better, but we don't know."
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Netanyahu, who met with President Barack Obama on Monday and Secretary of State Hillary Clinton on Tuesday, put the world on notice that his patience was wearing thin and that, if necessary, he would launch unilateral strikes.
Obama, who assured Netanyahu that he has Israel's "back", stressed that he sees a window for diplomacy with Iran, despite much speculation that Israel could soon mount a risky go-it-alone military operation.
The Obama administration says it does not believe Iran has taken a decision to develop a nuclear weapon, or that the time is right for military action, preferring to give biting new sanctions time to work.
But Israel claims the Islamic Republic may be on the cusp of "breakout" capability -- when it could quickly build a nuclear weapon.
Commenting on the divergence of views, Netanyahu acknowledged that there was a "fundamental difference" in the two country's approach.
"The United States is a big country, far away from Iran; we are a small country very close to them."
Referring to the speculation that Israel might act without US approval, Netanyahu recalled that it had done so before in a 1981 attack on an Iraqi nuclear facility.