Cliff Owen, Associated Press
U.S. United Nations Ambassador Samantha Power addresses the 2015 American Israel Public Affairs Committee (AIPAC) Policy Conference in Washington, Monday, March 2, 2015.

WASHINGTON — The Obama administration pushed ahead Monday with an effort to end its standoff with Israel, arguing that the focus on tensions between the allies obscured a larger truth that the United States would never jeopardize the Jewish state's security by allowing Iran to become a nuclear power.

Addressing this year's annual policy conference of the American-Israel Political Action Committee, the leading pro-Israel lobby, President Barack Obama's U.N. ambassador, Samantha Power, highlighted the billions of dollars in military assistance Washington provides and the constant defense the U.S. provides Israel at the United Nations. She spoke hours after Secretary of State John Kerry vigorously defended Israel before the U.N. Human Rights Council in Geneva.

"Our commitments to our partnership with Israel are bedrock commitments — rooted in shared, fundamental values, cemented through decades of bipartisan reinforcement," Power said, rreceding Israeli Prime Minister Benjamin Netanyahu to the dais. "This partnership should never be politicized and it cannot and will not be tarnished or broken."

Power, however, didn't give ground on Iran, the issue currently dividing the U.S. and Israel and one she said National Security Adviser Susan Rice would expound upon later in the day. Netanyahu addresses Congress Tuesday.

"We believe diplomacy is the preferred route to secure our shared aim. But if diplomacy should fail, we know the stakes of a nuclear-armed Iran as well as everyone here. We will not let it happen," Power said. In an apparent reference to reports that the deal could ease restrictions on Iran in its latter years, she added: "There will never be a sunset on America's commitment to Israel's security."

Iran says its nuclear program is solely for peaceful energy and medical research purposes. Negotiators are trying to reach a framework agreement by the end of the month and a full deal by July.

Echoing Kerry's remarks in Switzerland, Power called the U.N.'s focus on Israel's record cynical and one-sided in an era when "anti-Semitism is surging by every measure." She cited deadly attacks on Jews in France and Denmark, and rallies in Germany at which protesters chanted "Hamas, Hamas; Jews to the gas."

Washington opposed 18 "biased resolutions" at the U.N. General Assembly last September, she said. It cast the sole "no" vote when the Human Rights Council launched an investigation of human rights violations in last year's war in Gaza without mentioning Hamas. In the Security Council, the U.S. has tried to stop any resolution threatening Israel's security or undermining the pursuit of peace.