U.S. President Barack Obama is expected to hold on to his diplomacy-first stance over Iran's disputed nuclear program when he is meeting with Israeli Prime Minister Benjamin Netanyahu at the White House on Monday.

The president stated clearly on Sunday that he firmly believed that an opportunity still remains for his two-track approach, diplomacy and pressure, to succeed in stopping Iran from acquiring nuclear weapons.

However, the Iranian issue is sure to heat up in an election season in the United States, as members of Congress and Republican presidential candidates joined chorus of clamoring for a hardening position on Iran, while Israel insisted on its right to launch a preemptive strike on Iran's nuclear facilities.

Obama "takes no options off the table"

Obama and his top aides have stated time and again that Washington sought to prevent Iran from obtaining nuclear weapons, and was willing to "take no options off the table" to this end.

Despite onslaughts from a convergence of pro-Israel activists in an election year, Congress members and Republican presidential hopefuls accused Obama of being weak in backing a staunch ally and confronting a bitter foe.

Obama did not back down when he faced on Sunday an influential audience at the annual meeting of the American Israel public affairs committee, a powerful pro-Israel lobbying group in Washington.

He spoke of diplomacy when he talked about the shared goal of the United States and Israel on stopping Iran from getting nuclear weapons, though he tried to reassure Israel of U.S. commitments at great length at the same time.

"A nuclear-armed Iran is completely counter to Israel's security interests, but it is also counter to the national security interests of the United States," Obama said.

He said that Iranian nuclear weapons could fall into the hands of terrorist organizations, and trigger an arms race in one of the world's most volatile regions.

Drawing attention to the elaborate efforts made by Washington and its allies to tighten up the pressure on Iran, including the crippling sanctions in place, Obama stressed that "I firmly believe that an opportunity still remains for diplomacy -- backed by pressure -- to succeed."

He declared that as president and commander-in-chief, he has "a deeply held preference for peace over war," and he will only use force when the "time and circumstances" demand it.

In an apparent effort to placate Israel and its backers, Obama said he meant what he said when he stated he would "take no options off the table" in confronting Iran over its nuclear program.

"That includes all elements of American power" encompassing political, diplomatic and economic efforts as well as "a military effort to be prepared for any contingency," the president said.

Days earlier, Obama made his intentions known through a carefully choreographed interview with Jeffrey Goldberg, a national correspondent from The Atlantic monthly that is widely read among Jews in the United States.

The president, scheduled to meet with Netanyahu on Monday at the White House, clearly declared that his "no options off the table" included the "military component."

Obama said he would seek to persuade Netanyahu to postpone whatever plans Israel may have to bomb Iran's nuclear sites in the coming months.

"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 asked, arguing that military action would only delay, not prevent, Iran's acquisition of nuclear bombs.

As Obama has turned to a high gear for his reelection campaign, he is seen in no mood to have another war in the Middle East when he focuses on growth and job creation at home, the top concern of American voters.

Israel's patience wears thin

However, Israel's patience seems to wear thin as time goes on.

In January, Netanyahu said he saw Iran "wobble" under the sanctions, in particular under the threat by the U.S. and some European countries targeting its central bank and oil exports.

However, during his visit to Cyprus in February, the prime minister said "I hope that sanctions work, but so far they haven't worked."

Israel's Defense Minister Ehud Barak also said earlier in a bellicose tone that "whoever says 'later' may find that later is too late."

Israel sees Iran as an arch rival, as Iranian President Mahmoud Ahmadinejad has called for wiping Israel off the map several times.

Though Israel and its supporters want Obama to stop urging restraint on Israel and be more explicit about the "circumstances" under which Washington itself would launch a strike on Iran's nuclear sites, the Israeli prime minister, whose relationship with Obama has been uneasy, has avoided to show that he is pressing the White House hard.

"I have not set red lines and we are not seeking to set red lines to the United States," Netanyahu said in Canada on Friday on his way to Washington.

"We do ask to reserve the freedom of action of the state of Israel in the face of threats to wipe us off the map. I think that is something that any state would demand for itself," he said at a press conference with his Canadian counterpart Stephen Harper.

Tehran insists its nuclear program is for electricity generation and medical uses only, while the West suspects the Islamic republic is trying to develop nuclear weapons secretly.

However, a report released late last month by the International Atomic Energy Agency pointed out that Iran had expanded uranium enrichment activities in recent months.

Netanyahu said Iran must dismantle its underground nuclear facility in Qom, stop uranium enrichment and remove all enriched material on its soil except for what would be required of civilian use.

The White House rejected the suggestions, arguing Iran would never accept them and insistence of them would doom negotiations with the Islamic republic even before they begin, the New York Times said on Sunday.

Iran is now awaiting a reply from the six powers, including Britain, China, France, Russia, the United States and Germany, on whether they agree to reopen negotiations over its nuclear program.