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'Unbreakable' bond: Obama offers Netanyahu assurances over Iran

President Obama met with Israeli Prime Minister Benjamin Netanyahu at the Oval Office and discussed the crisis over potential Iranian nuclear weapons. Msnbc's Thomas Roberts has the latest.

Updated at 11:55 a.m. ET: WASHINGTON --  President Barack Obama, aiming to head off any premature Israeli strike on Iran, sought to assure Prime Minister Benjamin Netanyahu on Monday that the United States would always "have Israel's back" but said there was still time for diplomacy.

In a show of unity with an American leader with whom he has had a rocky relationship, Netanyahu said at the White House that both Israel and the United States stood together on the need to prevent Iran from obtaining nuclear weapons.

For his part, Obama said the "bond between our two countries is unbreakable."

The two men, sitting side by side and smiling at each other in the Oval Office, sought to present a united front in the Iranian nuclear standoff after weeks of mounting concern that Israel would preemptively strike Iran on its own.

Iran on radar as Obama talks to Israel supporters

"We believe there is still a window that allows for a diplomatic resolution," Obama said at one of the most consequential meetings of U.S. and Israeli leaders in years.

Even though Obama has offered assurances of stiffened U.S. resolve against Iran before the White House meeting, the two allies are still far apart on explicit nuclear "red lines" that Tehran must not be allowed to cross, and they have yet to agree on a time frame for when military action may be necessary.

"Both the prime minister and I prefer to solve this diplomatically," Obama said as he and Netanyahu began several hours of White House consultations. The U.S. will consider all options in confronting what it sees as the unacceptable outcome of an Iranian bomb, Obama said.

Obama said he would not hesitate to use military force against Iran but that talk of war has driven up oil prices. NBC's Mike Viqueira reports.

"Israel and America stand together," Netanyahu said. He added that Israel is a sovereign nation with the right to defend itself, a pointed reference to the main question hanging over Monday's high-stakes meeting: Whether to try to stop an Iranian bomb with a military attack in the next several months.

Netanyahu also made clear that Israel would be the "master of its fate" in deciding how to deal with Iran, which has called for the destruction of the Jewish state.

"It must have the ability to defend itself, by itself, against any threat," Netanyahu said, echoing remarks Obama made a day earlier in a speech to the powerful pro-Israel lobby AIPAC.

Iran focus as Obama talks to Israel backers

Obama has been urging Israel to allow sanctions more time to work against Iran's nuclear ambitions while balancing that with assurances of his resolve to do whatever is necessary to keep the Islamic republic from becoming a nuclear-armed state.

At the White House meeting, Obama told Netanyahu the United States reserved "all options" in dealing with Iran. The president has made clear that would include a possible military component.

In a meeting between the two world leaders, Israel's Prime Minister Benjamin Netanyahu did not back down from possible military action against Iran, while President Barack Obama said there is a still a window during which sanctions could work. NBC's Andrea Mitchell reports.

"We do not want to see a nuclear arms race in the most volatile region in the world," Obama said.

While Obama and Netanyahu -- who have had a strained relationship -- will share intelligence information, a source close to the administration told Reuters earlier that there was little reason to believe they would make significant progress toward bridging key differences on a common threshold for military action.

"They'll be looking for mutual understandings and may find a few, but the biggest problem is they're working on different clocks," the source said.

The president was expected to tell Netanyahu in private that although the U.S. is committed to Israel's security it does not want to be dragged into another war. Obama is unlikely to spell out U.S. "red lines" that would trigger a military response, despite Israeli pressure to do so.

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Reuters and The Associated Press contributed to this report.