ABOARD THE ROMNEY CAMPAIGN PLANE-- Mitt Romney said Friday following a conversation with Israeli PM Benjamin Netanyahu that he was hopeful that the U.S. wouldn't have to use military force to halt Iran's progress toward nuclear weapons.

The Republican presidential nominee told reporters traveling with him that he thought a peaceful resolution in Iran was still within reach, though Romney cautioned that it was important to leave open the option to use military force.

"I do not believe that in the final analysis we will have to use military action," Romney told reporters traveling with him from Philadelphia to Boston. " I certainly hope we don’t have to."

The GOP presidential nominee, who has long advocated the U.S. taking a tougher stand against the Iranian regime, said despite his optimism it would be important in future negotiations with Iran to keep a military option on the table.

"It must be something which is known by the Iranians as a possible tool to be employed to prevent them from becoming nuclear," Romney said of a possible use of military force. "But I certainly hope that we can prevent any military action from having to be taken."

The remarks came roughly one hour after Romney concluded his telephone conversation with the Israeli prime minister, who delivered an address to the United Nations yesterday in which he advocated for the drawing of a bright "red line" with Iran's leadership - offering a clear point of no return which would trigger Western military action and hopefully dissuade the regime from further pursuing its nuclear program.

Netanyahu also spoke by phone with President Barack Obama earlier today, and Romney was asked to draw a distinction between his views on Iran and those of the president. Romney said the administration's policies have moved more to mirror with his own views over time, pointing to newer, more aggressive sanctions placed on the Iranian regime as evidence, and saying he would continue to see how well Obama would match his rhetoric to his actions.

"His words more recently are more consistent with the words that I’ve been speaking for some time," Romney said. "And we’ll see what actions he pursues."

President Obama and his Russian counterpart, Vladimir Putin, met on Monday for the first time since the violent uprising in Syria began to discuss possible actions to limit further bloodshed in the meeting.

Putin, who reassumed the presidency of Russia earlier this year, met with Obama in bilateral talks that stretched for some time; both leaders were in Mexico for this week's G-20 summit.

Both leaders said they found common ground on the conflict, but shed little light on the steps upon which they agreed were needed to mount the violence between the Syrian people and the country's rulers. Putin is an ally of Syrian President Bashar al-Assad and has generally resisted imposing more sanctions on that regime.

Putin shared just two sentences on the issue of Syria, speaking through a translator: “We also discussed international affairs, including the Syrian affair. From my perspective, we've been able to find many commonalities pertaining to all of those issues.”

Obama said the leaders “agreed that we need to see a cessation of the violence, that a political process has to be created to prevent civil war, and the kind of horrific events that we've seen over the last several weeks, and we pledged to work with other international actors including the United Nations, [UN Special Envoy] Kofi Annan, and all the interested parties in trying to find a resolution to this problem.”

At a press briefing after the two leaders met, Ben Rhodes, deputy national security adviser for strategic communications, stressed that Putin supports a political transition in which Assad loses power, even if the Russian president is not as vocal about such views as other leaders. 

“It's true the Russians have not publicly issued the same type of call for Assad to step down,” Rhodes acknowledged.

During the meeting, President Obama also said the two leaders discussed negotiations with Iran over its nuclear program, stressing the “shared approach” among members of the P5+1, a group that includes the U.S., Britain, Russia, France and China plus Germany, in their dealings toward the Iranian regime.

That emphasis on a shared approach highlights Russia's opposition to unilateral sanctions against Iran, such as the ones installed by the United States against countries that do business with Iranian oil companies. Just last week, Russian foreign minister Sergey Lavrov said during a press conference in Iran that “unilateral sanctions by others will never have a positive and constructive outcome.”

Obama also made a passing reference to an issue that has been a key factor in US-Russia relations, but over which the president recently got into domestic political hot water: missile defense.

During a meeting in March with then-Russian president Dmitry Medvedev, Obama was caught on a hot microphone saying he would have “more flexibility” on the missile shield issue after the November elections, to which Medvedev uttered the now-infamous response, “I will transmit this information to Vladimir.” Republicans pounced on the exchange, saying it represented American weakness on the international stage.

But today, Putin gave little indication of just what was transmitted, as the only thing either leader said on the topic was that it was discussed among a “range of strategic issues,” according to Obama, and that they “resolved to continue to work through some of the difficult problems involved there.”

The interaction between the two leaders, meeting for just the second time, was perceived by the press in the room as somewhat chilly. As the group of journalists was ushered out of the room, “Messrs. Obama and Putin remained seated, their interpreters had stepped away, sitting side-by-side on the other side of the room -- and they just stared straight ahead. No interacting or chit chatting,” one pool reporter wrote.

But administration officials later urged observers not to read in to the encounter.

“This isn’t the first Body Language-Gate that we've had with the Russians,” Rhode said, noting that relations between Obama and Medvedev, who are considered to have a more friendly relationship than that between Obama and Putin, have also been perceived as frosty.

“That's just his style. I would encourage you not to read too much into that as part of relationship,” said U.S. ambassador to Russia Mike McFaul, also at the briefing today.

Vice President Joe Biden on Tuesday vigorously defended the Obama administration's record on Israel, crediting President Obama for strengthening America's position in the region and for imposing "the most damaging sanctions in this century" to prevent Iran from obtaining a nuclear weapon.

"We were the problem," Biden said of the global view of the United States before the president took office. "We were diplomatically isolated in the world, in the region, in Europe. The international pressure on Iran was stuck in neutral."

"We were neither fully respected by our friends nor feared by our opponents," he told guests at an annual convention of the Rabbinical Assembly. "Today it is starkly, starkly different."

The vice president argued that Obama "deserves the credit" for coordinating harsh sanctions against Iran that he says are bringing that nation's negotiators back to the table, although he warned that the time for diplomacy may be waning.

"The window has not closed in terms of the ability of the Israelis if they choose on their own to act militarily," he added, noting that he understood Israel's desire not to "contract out" its security to allies like the United States.

Biden won sustained applause from the crowd by repeating that America does not have "a policy of containment" towards Iran. "We will prevent Iran from acquiring a nuclear weapon by whatever means needed, period. Period," he said.

Citing dissension between Iran's own leaders, the vice president also predicted that stridently anti-Israel Iranian leader Mahmoud Ahmedinijad will be forced from power within two years.

He did not mention GOP presidential candidate Mitt Romney by name, although the former Massachusetts governor's campaign later ripped his remarks about America's past isolation in the region as "wrong and completely inappropriate."

"All too often, President Obama and his administration have sought to blame America first, yet Vice President Biden’s reckless statement today blaming America for – of all things – the progress of Iran’s nuclear weapons program, has reached a new low," said Romney policy director Lanhee Chen in a statement. "The problem is not America."

Biden, who was elected to the Senate at age 30 and served at the helm of the Senate Foreign Relations Committee, noted that his youth made him unique among his peers and offered him the opportunity to cultivate many mentors in the upper chamber. "I was the young kid. I was like the only woman or the only African-American," he said.

The vice president, who has been in the spotlight for his comments Sunday in support of same sex marriage, did not mention the controversy on Tuesday, although he  alluded to his famous penchant for candor that occasionally his political allies.

"No one's ever doubted I mean what I say," he said. "The problem is I sometimes say all that I mean."

The Obama administration approved further sanctions Friday on Iranian crude oil exports after determining that oil supplies were adequate to justify the new penalties.

President Obama announced the new sanctions, which were written into law by Congress and will take effect at the end of June, which actually bar foreign banks from doing business in the United States if they buy or sell Iranian crude oil.

The White House was careful not to speculate on how this would affect global oil and gas prices. A Democratic aide said that while congressional leadership had been notified of the president's decision before it became public, there was no mention of the strategic petroleum reserve in that notice.

According to a statement from Press Secretary Jay Carney, while the administration believes "the oil market became increasingly tight over the first two months of 2012" and "that tightness remains today," there still "appears to be sufficient supply of non-Iranian oil to permit foreign countries to significantly reduce their import of Iranian oil."

The State Department believes there are currently 23 countries that publicly import Iranian oil. The State Department announced exemptions from these sanctions last week for 11 of those countries.  Those 11 countries (Belgium, the Czech Republic, France, Germany, Greece, Italy, the Netherlands, Poland, Spain, the United Kingdom, and Japan) have taken steps to significantly reduce their imports of Iranian crude oil.

Senior administration officials say that the exemptions list is not finalized, and they are still in consultations with allies like South Korea and Turkey about how to proceed. This was one of the issues that came up during Obama's talks with South Korean President Lee Myung-bak earlier this week when the President was in Korea for the Nuclear Security Summit.  There were indications that South Korea had an interest in pursuing a reduction in importing Iranian oil and avoiding these sanctions.

Two other countries on the sanctions list, India and China, are significant importers of Iranian oil.  A senior administration official says that even if these two countries do not reduce their imports, the moves by the U.S. government will put pressure on Iran "above and beyond anything it's experienced before." And the official clarified that they continue to have a dialogue with both India and China.