Prime Minister Benjamin Netanyahu told US President Barack Obama Monday that Israel must remain the "master of its fate" in a firm defense of his right to mount a unilateral strike on Iran.

Netanyahu and Obama met for delicate Oval Office talks taking place amid clear differences on the imminence of the nuclear threat from Iran and after weeks of speculation that Israel may mount go-it-alone military action.

"Israel must have the ability always to defend itself, by itself, against any threat," Netanyahu said in a short, but impassioned comments to cameras at the start of a meeting with Obama, with whom he has had sometimes strained relations.

"After all, that is the very purpose of the Jewish state, to restore to the Jewish people control over our destiny.

"That's why my supreme responsibility as prime minister of Israel is to ensure that Israel remains the master of its fate," said Netanyahu, who ruffled Obama's feathers last year with a stunning lecture in the Oval Office.

The Obama administration has signaled that it does not yet believe Iran has taken a choice to develop a nuclear weapon, or that the time is right for military action, preferring to give biting new sanctions time to work.

Israel, which sees an Iranian nuclear weapon as a threat to its existence, however believes that Iran may be on the cusp of "break out" capacity -- the moment when it could quickly produce weapons-grade uranium.

Obama recognized that it was "unacceptable" for Israel to tolerate Iran developing a nuclear weapon after calling for the Jewish state's destruction and again refused to rule out eventual US military action.

"I reserve all options and my policy here is not going to be one of containment.

"My policy is prevention of Iran obtaining nuclear weapons ... when I say all options are on the table, I mean it," Obama said, a day after telling Washington's top pro-Israel lobby that "loose talk" of war was damaging.

The president, seeking to preserve a way Iran could assuage international anxiety over its nuclear program without war, said he believed a diplomatic solution to the showdown was still possible.

"We do believe there is still a window that allows for a diplomatic resolution to this issue."

Obama also took a veiled swipe at Republican presidential candidates who have slammed his approach to Iran as appeasement and claim he has failed to properly protect Israel.

"Our commitment to the security of Israel is rock solid," he said. "The United States will always have Israel's back."

Many analysts argue that Washington fears that an early, preemptive strike from Israel could trigger a fierce reaction from Iran, unleash further turmoil in the Middle East and drag Washington into a new Middle East war.

There are also fears that Israel does not possess sufficient military capacity to end Iran's underground pursuit of the nuclear arsenal it denies seeking, and could at best set back the program just a few years.

Washington also warns that tensions over Iran benefit the Islamic Republic by hiking the price of oil, and rock the global petroleum market in a way that could crimp the slow yet building economic recovery.

Obama warned in an interview with the Atlantic magazine last week that a premature strike could inadvertently help the Iranian regime.

"At a time when there is not a lot of sympathy for Iran and its only real ally (Syria) is on the ropes, do we want a distraction in which suddenly Iran can portray itself as a victim?" Obama said.

The stand-off has pushed the Israeli-Palestinian conflict into the background, although Obama did raise the stalled talks.

He pledged to work for "a calmer set of discussions between the Israelis and the Palestinians" in a bid to seek a "peaceful resolution to that long-standing conflict."

But he added: "it is a very difficult thing to do in light of the context right now."