By Amie Parnes and Jeremy Herb The Hill

President Obama said Monday there is time to preventIranfrom securing a nuclear weapon through diplomacy and not a military strike at the outset of a high-stakes meeting at the White House with Israeli Prime Minister Benjamin Netanyahu.
For the second day in a row Obama said theres still a window that allows for a diplomatic resolution" to the Iranian nuclear threat and that the United States together with other countries would continue to tighten pressure" and put forth the most crippling sanctions" to date.
But Obama who in a Sunday address to the American Israel Public Affairs Committee emphasized that he had Israels back" said that if the Iranian regime didnt move in the right direction he would consider other options.
As I indicated yesterday in my speech when I say all options are on the table I mean it" Obama said.
Obama and Netanyahu highlighted U.S.-Israeli unity during a brief appearance before the media but differences remain between the two countries over just how big the window is for a diplomatic resolution.
On Monday Netanyahu sitting beside Obama in the Oval Office saidIsraelmust reserve the right" to act unilaterally.
Israelmust have the ability to defend itself by itself against any threat" Netanyahu said. When it comes toIsraels securityIsraelhas the right the sovereign right to make its own decisions. I believe thats why you appreciate Mr. President thatIsraelmust reserve the right to defend itself.
My supreme responsibility as prime minister ofIsraelis to ensure thatIsraelremains the master of its fate" Netanyahu added.
The Obama-Netanyahu meeting on Monday lasted about two hours a senior administration official said.
The official stressed that diplomacy is the best way to solve the potential nuclear problem and that theUnited States is building a coalition of nations while allowing space for diplomacy becauseIran does not have a nuclear weapon.
The official said theUnited Stateswould have enough time to make a decision on military action should the Iranian government choose to obtain a weapon. Israeli leaders are convinced on Obamas seriousness to the issue the official added.
In public Obama sought to assure Netanyahu that all options remain on the table to preventIranfrom obtaining a nuclear weapon.
I reserve all options and my policy is not going to be one of containment" Obama told Netanyahu in the Oval Office before a gaggle of reporters. My policy is prevention ofIranobtaining nuclear weapons."
Netanyahu is expected to press Obama to more clearly define the red lines for when theUnited Stateswould act military to stopIran. Analysts say that the Israeli prime minister is looking for assurances that if Israeli does not act the Obama administration would because Israels military capability gives them less time to be able to disable Irans nuclear program.
The prime minister who thanked Obama for his strong" speech on Sunday before the American Israeli Public Affairs Committee also touted his countrys relationship with theUnited States.
We face common enemies" Netanyahu said. Irans leaders know that too. For them youre the great Satan. Were the little Satan. For them we are you and you are us. And you know something Mr. President? At least on that last point I think theyre right."
As the two leaders wrestled with arguably their weightiest issue to date the meeting on Monday appeared far less tense than their meeting last year when Netanyahu appeared to lecture Obama on the history ofIsrael.
On Monday before a one-on-one meeting followed by a working lunch the two leaders both highlighted their common bond sending a strong message toIranand other nations about their unity.
As Ive said repeatedly the bond between our two countries is unbreakable Obama said. My personal commitment a commitment that us consistent with the history of other occupants of this Oval Office is rock solid and as Ive said to the prime minister in every single one of our meetings the United States will always have Israels back when it comes to Israels security."
Natan Sachs a fellow at the Brookings InstitutionsSabanCenter said Mondays meeting will help Obama and Netanyahu coordinate their private strategies as well as their public messages.
Confusion and mixed messages create uncertainty which can be very dangerous in a situation thats ripe for war Sachs said.
Speaking to Netanyahu on Monday Obama said its unacceptable fromIsraels perspective to have a country with a nuclear weapon that has called for the destruction ofIsrael."
But as I emphasized yesterday it is profoundly in theUnited Statess interest as well to preventIranfrom obtaining a nuclear weapon he added. We do not want to see a nuclear arms race in one of the most volatile regions of the world. We do not want the possibility of a nuclear weapon falling into the hands of terrorists and we do not want a regime that has been a state sponsor of terrorism being able to feel that it can act even more aggressively or with impunity as a consequence of its nuclear power.