WASHINGTON (AP) — Seeking to lower tensions, Benjamin Netanyahu and U.S. officials cast their dispute over Iran as a family squabble on Monday, but the Israeli leader still claimed that President Barack Obama did not — and could not — understand his nation's vital security concerns.

"American leaders worry about the security of their country," Netanyahu said as he opened a controversial trip to Washington. "Israeli leaders worry about the survival of their country."

Netanyahu's remarks to a friendly crowd at a pro-Israel lobby's annual conference amounted to a warm-up act for his address to Congress Tuesday, an appearance orchestrated by Obama's political opponents and aimed squarely at undermining the White House's high-stakes bid for a nuclear deal with Iran.

Netanyahu tried to paper over his personal differences with Obama, insisting he was not in Washington to "disrespect" the president and saying that any reports of the demise of U.S.-Israel ties were "not only premature, they're just wrong."

Still, Netanyahu made clear that he would not hold back in criticizing the U.S.-led nuclear negotiations with Iran.

"I have a moral obligation to speak up in the face of these dangers while there is still time to avert them," he told the cheering crowd of 16,000 at the American Israel Public Affairs Committee conference. He said Israel had a unique understanding of the security concerns posed by any Iranian pursuit of a nuclear bomb because of its position in a "dangerous neighborhood."

Obama spoke dismissively of Netanyahu's warnings about the risks of an Iran deal, saying the prime minister had previously contended Iran would not abide by an interim agreement signed in 2013 and would get $50 billion in sanctions relief, a figure the U.S. says is far too high.

"None of that has come true," Obama said in an interview with Reuters.

As Netanyahu spoke, Secretary of State John Kerry was in Switzerland opening another round of talks with Iran, as the parties try to cobble together a framework agreement before an end-of-March deadline. Obama views the prospect of a nuclear accord with Iran as a central component of his foreign policy legacy — as much as Netanyahu views blocking such a deal as a component of his own.

Netanyahu has been wary of Obama's diplomatic pursuits with Iran from the start, fearing the U.S. will leave Tehran on the cusp of being able to build a bomb. As the outlines of a deal have emerged and the deadline has drawn near, his criticism has become more forceful.

U.S. officials have reported progress toward a prospective agreement that would freeze Iran's nuclear program for at least 10 years but allow the Iranians to slowly ramp up in later years. Netanyahu has said that framework suggests the U.S. and its partners have "given up" on stopping Iran. In response, Kerry has said America's historic support of Israel suggests Washington deserves the benefit of the doubt.

While Obama and Netanyahu have never gotten along personally, the rift over Iran has sunk their relationship to a new low. The White House has criticized the prime minister's address to Congress as a breach of diplomatic protocol and, officials have publicly questioned his judgment on the merits of the Iran deal.

Obama has no plan to meet with Netanyahu this week, citing Israel's March 17 elections and longstanding U.S. policy to avoid appearing to play favorites in foreign voting.

Netanyahu's remarks at AIPAC were bracketed by speeches from a pair of senior U.S. officials: U.N. Ambassador Samantha Power and National Security Adviser Susan Rice.

Power, softening the recent harsh tone, spoke warmly of U.S.-Israeli ties, saying the relationship was rooted in "shared fundamental values" and "should never be politicized." She highlighted the billions of dollars in military assistance Washington delivers as well as the constant defense the U.S. provides Israel at the United Nations.

On Iran, Power said the U.S. shares Israel's commitment to preventing Tehran from obtaining a nuclear weapon. While Obama prefers to achieve that goal through diplomacy, she suggested he would be willing to take more muscular steps if necessary.

"If diplomacy should fail, we know the stakes of a nuclear-armed Iran," she said. "We will not let it happen."

Rice was expected to deliver a more specific rebuttal to Netanyahu's criticism of the U.S.-led nuclear negotiations. She has been among the most outspoken critics of the prime minister's plan to address Congress, calling it "destructive" to the U.S.-Israel relationship.

Kerry and Netanyahu spoke by phone over the weekend, but it did not appear the prime minister would hold any in-person meetings with Obama officials. Vice President Joe Biden was traveling in Guatemala on a trip announced only after the Netanyahu address was revealed. Netanyahu did plan to meet with a bipartisan group of senators after the congressional address, according to his published schedule.

As Senate president, Biden would have sat behind Netanyahu during his speech to Congress. Utah Sen. Orrin Hatch, the senior Republican senator, was expected to take Biden's place.

House Speaker John Boehner plans to present Netanyahu a bust of former British Prime Minister Winston Churchill, a gift chosen because the two men will be the only foreign leaders to have addressed Congress three separate times.

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AP Diplomatic Writer Matthew Lee in Geneva and AP writers Bradley Klapper and Deb Riechmann in Washington contributed to this report.

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