U.S. President Barack Obama and Israeli Prime Minister Benjamin Netanyahu held a high-profile meeting at the White House on Monday, with Iran's controversial nuclear program as the sole focus on their agenda.

It is still not clear if the two-hour closed-door meeting has helped to smooth over the two leaders' differences over how to tackle the nuclear threat posed by Tehran, observers said.

During a press availability before the meeting, while reiterating the U.S. "unshakable" commitment to Israel's security, Obama insisted there was still a "window" for a diplomatic solution to Iran's nuclear issue.

However, Netanyahu appeared to be sticking to his hard-line stance, stressing that Israel reserved the right to defend itself "against any threat," notably from Tehran.

While Netanyahu may give Obama more time to pursue diplomatic solutions, Israel could eventually resort to military action, analysts said, adding that the militaries of the two countries may have already begun to work out contingency plans in case of such a potential scenario.

REAFFIRMING COMMITMENT TO ISRAEL

Reports on Israel's military intention started to surface from the second half of last year. Recently, Israel has been taking an increasingly hard-line stance on Iran's nuclear program, with Defense Minister Ehud Barak saying openly that if Israel must strike eventually, it should do so as early as this spring or summer.

Analysts said Barak's remarks reflected a growing anxiety on the part of Israel, who is worried that Iran's nuclear program would soon enter the so-called "zone of immunity," where its facilities would be scattered around and protected in underground bunkers, making military strikes unfeasible.

Some believed that Netanyahu, during his Washington visit, was trying to seek guarantees from Obama to stop Iran's nuclear program, even with military force.

In a bid to reassure its ally, Obama reaffirmed his administration's "unshakable" commitment to Israel, saying the U.S. "will always have Israel's back" when it comes to that country's security.

Obama also made it clear that his administration did not have a containment policy toward Tehran.

"My policy is to prevent Iran from obtaining nuclear weapons," he said, adding that he meant it when he said all options were on the table.

WINDOW FOR DIPLOMACY

While trying to soothe Israel's growing concerns, Obama insisted there was still a window for a diplomatic solution on Iran's nuclear issue.

Obama defended his diplomacy-first stance over Tehran's disputed nuclear program, arguing that amid growing international pressure, it was possible that Iran's leadership would change course.

Analysts said Obama was trying to appeal to Israel for more time to allow sanctions to work, and at least delay a potential strike.

TO STRIKE OR NOT TO STRIKE

But it should not be ignored that Netanyahu, and many in Israel, have long viewed Iran's nuclear ambition as an "existential threat" to the Jewish state.

Netanyahu on Monday made it clear to Obama that Israel reserved the right to defend itself "against any threat," and to "make its own decisions."

The hard-line prime minister added that his supreme responsibility was to ensure the Jewish state "remains the master of its fate."

Addressing the annual meeting of the American Israel Public Affairs Committee (AIPAC), an influential pro-Israel lobbying group in Washington on Sunday, Shimon Peres, the 89-year-old Israeli president, said Iran's nuclear ambition must and will be stopped.

"Iran will not have a nuclear bomb," he asserted.

Obama, meanwhile, told the meeting that Washington understood that no Israeli government would tolerate a nuclear-armed Iran.

"And so I understand the profound historical obligation that weights on the shoulders of Bibi Netanyahu and Ehud Barak, and all of Israel's leaders," he said.

It is notable that the meeting also involved U.S. defense secretary Leon Panetta, defense minister Barak, and other senior military and intelligence officials.

And in an unusually high frequency, a string of top U.S. and Israeli national security and defense officials have visited each other's capitals recently.

Obama described the level of consultations between the two allies' military and intelligence services as "unprecedented."

He said he would make sure that the consultations would continue during "what would be a series of difficult months in 2012."

It may sound a little far-fetched to say that the unusually frequent military exchanges are only aimed at avoiding a conflict. In fact, speculation is rife that the two counties may be preparing contingency plans in case there would be an attack.

To strike or not to strike, that is the question. At the AIPAC meeting, a Jewish journalist, responded in an American way when asked about it: "That is really a one-million-dollar question."

Indeed, how the situation would evolve hinges on a host of variable factors which could have an impact on the final outcome.