WASHINGTON (Reuters) - President Barack Obama appealed to Benjamin Netanyahu on Monday to give sanctions time to curb Iran's nuclear ambitions, but the Israeli prime minister offered no sign of backing away from possible military action, saying his country must be the "master of its fate."
The two men, who have had a strained relationship, sought to present a united front in the Iranian nuclear standoff as they held White House talks. But their public statements revealed differences over how to prevent Iran from developing nuclear weapons.
Behind closed doors, however, Netanyahu confirmed to Obama what the president has already stated publicly - that Israel has yet to decide whether to hit Iran's nuclear sites but retains the right to resort to military action, a source close to the talks said.
Kicking off one of the most consequential meetings of U.S. and Israeli leaders in years, Obama and Netanyahu made no mention of lingering disagreements over what Washington fears could be an Israeli rush to attack Iran's nuclear program in the coming months.
Obama, facing election-year pressure from Israel's U.S. supporters and Republican presidential contenders, sought to assure Netanyahu the United States was keeping its own military option open as a last resort and "has Israel's back."
But he also urged Israeli patience to allow sanctions and diplomacy to work.
Netanyahu, who has made clear that Israel is operating on a shorter timeline than the United States, said in public that Israel was entitled to "defend itself, by itself." Israel sees Iran's nuclear program as a threat to its existence, though Tehran insists it has only peaceful purposes.
"We do believe there is still a window that allows for a diplomatic resolution to this issue," Obama said, even as he sought to convince Netanyahu of U.S. resolve against Iran.
Given his chance to speak, Netanyahu said his "supreme responsibility as prime minister of Israel is to ensure that Israel remains the master of its fate."
Even though Obama has ratcheted up his tone against Iran in recent days, he and Netanyahu went into the talks divided over how quickly the clock is ticking toward possible military action. The meeting appeared unlikely to change that.
In private, the leaders made no concrete decisions but looked at both the price of taking action against Iran - which could spike oil prices and sow global economic upheaval - and the consequences of inaction, which could lead to a nuclear arms race in the Middle East.
They remain far apart on any explicit nuclear "red lines" that Iran must not be allowed to cross, and they have yet to agree on a time frame for when military forces might be needed.
There was no sign from Monday's talks that Obama's sharpened rhetoric against Tehran and his calls for restraint by Israel would be enough to delay any Israeli military plans against Iran, which has called for the destruction of the Jewish state.
Despite that, the body language between the two leaders was a stark contrast to their last Oval Office meeting in May 2011 when Netanyahu lectured Obama on Jewish history and criticized his approach to Israeli-Palestinian peacemaking.
This time, Obama and Netanyahu appeared businesslike but cordial as they sat side-by-side, chatting amiably as reporters entered the room and sometimes nodding when the other spoke.
Obama's encounter with Netanyahu was considered crucial to preserving the trust of America's closest Middle East ally, which fears that time is running out for an effective Israeli strike on Iran, and to counter election-year criticism from Republican rivals who question his support for the Jewish state.
He is also trying to tamp down increasingly strident talk of another war in the region, which could have damaging repercussions for the fragile U.S. economic recovery - a consequence that could threaten his re-election chances.
Speculation is mounting that Israel could opt to act militarily on its own unless it receives credible guarantees that the United States will be ready to use force against Iran if international sanctions and diplomacy fail.
Israel, believed to be the only nuclear weapons power in the Middle East, fears Iranian nuclear facilities may soon be buried so deep that they would be invulnerable to its bunker-busting bombs, which are less powerful than those in the U.S. arsenal.
Israel insists that military action against Iran would be warranted to prevent it from reaching nuclear weapons capability, as opposed to when it actually builds a device. Washington has not embraced that idea.
U.S. officials say that while Iran may be maneuvering to keep its options open, there is no clear intelligence that the country has made a final decision to pursue a nuclear weapon.
Obama said both he and Netanyahu "prefer to resolve this diplomatically" and also understand the cost of military action.
Netanyahu did not echo that sentiment, saying instead: "If there's one thing that stands out clearly in the Middle East today, it's that Israel and America stand together."
After talks with Obama and his aides and lunch with the president, Netanyahu told reporters, "They understood Israel's position that it has a right to defend himself."
What is clear is the potential political liability for Obama's re-election bid if hostilities break out in the Middle East before the November 6 U.S. presidential election.
Netanyahu's visit came one day before the pivotal "Super Tuesday" round of Republican primaries, with Obama's Republican rivals seizing on the chance to accuse him of being weak in backing a staunch ally and in confronting a bitter foe.
Relations with Netanyahu have thawed over the past year as Obama has taken a tougher line on Iran while refraining from any new Middle East peace drives.