In Israel, Obama Vows to Prevent Nuclear Iran

JERUSALEM, March 20, 2013 — -- Seeking to reassure the United States's primary ally in the Middle East, President Obama today told Israeli Prime Minister Benjamin Netanyahu that his administration remains committed to doing "what is necessary" to prevent Iran from obtaining a nuclear weapon.

"We do not have a policy of containment when it comes to a nuclear Iran. Our policy is to prevent Iran from acquiring a nuclear weapon," Obama told reporters at a joint press conference after a series of closed-door meetings with Israeli leaders.

"The United States will continue to consult closely with Israel on next steps. And I will repeat, all options are on the table," he said.

It's no secret that Obama and Netanyahu have had a rocky relationship, although it was hard to tell by the way the two leaders publicly lauded each other and joked around.

During the American presidential campaign, Republicans alleged that President Obama was not committed to protecting Israel, but today Obama and "Bibi," as he called him, appeared at ease in front of the press.

Netanyahu even placed Obama's commitment to Israel's right of self-defense above that of any other U.S. president.

"I appreciate the fact that the president has reaffirmed, more than any other president, Israel's right and duty to defend itself, by itself, against any threat. We just heard those important words now. And I think that sums up our -- I would say, our common view," he said.

That does not mean there are not differences.

Netanyahu was firm in his belief that there must be a "credible threat of military action" to stop Iran's nuclear program.

The White House, however, continues to prefer to "resolve this diplomatically," according to Obama. "And there's still time to do so."

Israeli President Shimon Peres told ABC News' Jonathan Karl that there is no doubt in his mind that if there was a military strike against Iran, it would be led by the U.S.

When asked if a military strike would be necessary to stop Iran, Peres explained, "The one that can decide that and the one who has the capacity to implement it clearly, is the United States of America. Israel should not go alone when the United States is determined and clear on it."

Obama Pledges to Investigate Chemical Attack Allegations in Syria

On the escalating crisis in Syria, Obama said the U.S. is investigating an alleged chemical weapons attack, but that he remains "deeply skeptical" of President Bashar al-Assad's claim that rebels have used such weapons.

"The broader point is, is that once we establish the facts, I have made clear that the use of chemical weapons is a game changer," he said.

But Obama said he would seek to avoid unilateral U.S. action in Israel. Calls for an elevated American presence and potentially even the commitment of U.S. troops have grown, particularly from U.S. Senators Lindsey Graham and John McCain.

"I want to make sure that we're working as an international community to deal with this problem because I think it's a world problem, not simply a United States problem or an Israel problem or a Turkish problem," said Obama.

Obama Tells Israel "Our Alliance is Eternal"

Arriving here this morning for his first presidential visit to Israel, President Obama sought to reassure Israelis of the strong support from the U.S. as they face increasing threats in the region, declaring "our alliance is eternal."

Standing on the tarmac in Tel Aviv, Obama said it was "no accident" that he chose Israel for the first foreign trip of his second term.