Israeli Prime Minister Benjamin Netanyahu speaks at a news conference near Jerusalem Wednesday. (Nir Elias/Reuters)

Tensions between the White House and Benjamin Netanyahu escalated Wednesday as top administration officials condemned the Israeli prime minister’s plan to address Congress next week and Netanyahu accused six world powers, including the United States, of “giving up on their commitment” to prevent Iran from obtaining a nuclear weapon.

The unusually public spat marked one of the lowest points in a relationship that has long bonded the two countries. Although the new round of recriminations reflected the frosty personal relations between President Obama and Netanyahu, it came at a critical juncture in multilateral talks designed to prevent Iran from using a civilian program to develop a nuclear weapon.

The prime minister has said the unfolding deal — to which Iran has not yet agreed — could pose an existential threat to the Jewish state. Obama, however, considers a deal a potential legacy that could ease nuclear tensions, lift trade restrictions on Iran and alter the region’s strategic calculus.

Congressional Democrats have been caught in the middle of the dispute. On Wednesday, Sen. Timothy M. Kaine (D-Va.) became the fourth senator to say he would skip Netanyahu’s speech, calling its timing “highly inappropriate.” Several members of the House also have said they will boycott the speech.

The latest volley of high-level criticism began when national security adviser Susan E. Rice, appearing Tuesday night on “Charlie Rose,” condemned Netanyahu’s decision to accept the invitation of House Speaker John A. Boehner (R-Ohio) to appear at a joint meeting of Congress shortly before Israel’s elections.

At a hearing of the House Foreign Affairs Committee, Secretary of State John Kerry took a shot at Israeli Prime Minister Benjamin Netanyahu over sanctions with Iran. (AP)

By bypassing the White House, dealing only with GOP leaders and scheduling the speech just before Israelis vote, Netanyahu had “injected a degree of partisanship, which is not only unfortunate,” Rice said, “I think it’s destructive of the fabric of the relationship.”

At a Likud political convention in the Maale Adumim settlement just east of Jerusalem, Netanyahu fired back. “I respect the White House and the president of the United States, but on such a critical topic that could determine whether we exist or not, it is my duty to do everything to prevent this great danger to the state of Israel,” he said.

Congress could play a critical role in the Iran talks. It is weighing whether to add new sanctions to the current ones.

The existing sanctions, and those adopted by the European Union, are widely viewed as having helped push Iran to the bargaining table.

But Obama has vowed to veto any new sanctions and has urged Congress to wait at least a month for the outcome of the negotiations. Obama has said that if the talks fail, he will move to tighten economic restrictions.

Secretary of State John F. Kerry defended the administration’s negotiations in testimony before the House Foreign Affairs Committee — and took a swipe at Netanyahu.

“I’ll tell you, Israel is safer today with the added time we have given and the stoppage of the advances of the Iranian nuclear program than before,” Kerry said. Referring to the accord that eased sanctions slightly while negotiations took place, he said: “We got that agreement — which, by the way, the prime minister opposed. He was wrong. And today he’s saying we should be extending that interim agreement.”

President Obama says not meeting with Israeli Prime Minister Benjamin Netanyahu in March is standard protocol for foreign leaders running in an election. (Reuters)

No love has been lost between Obama and Netanyahu.

“This is clearly the most dysfunctional relationship between an American and Israeli leader,” said Aaron David Miller, a vice president at the Wilson Center and a former U.S. negotiator and adviser in Republican and Democratic administrations. Moreover, he said, “the durability is troubling.”

He said that earlier tensions preceded incremental peace accords but that Obama and Netanyahu remain far apart on basic issues and that Kerry’s efforts to bring Israel and Palestinians together failed.

Now their personal tensions have put Democratic lawmakers in awkward positions that threaten bipartisanship when it comes to Israel.

Democrats have been wrestling over whether to boycott the speech, as senior Obama administration officials plan to do. This will be the third time Netanyahu has addressed the full Congress, tying Winston Churchill’s record.

Because Netanyahu did not arrange his visit through the White House, Obama has said that he will not meet with him, and Vice President Biden has made plans to travel abroad.

“This puts Democrats in a position where they have to choose between their support for Israel and their Democratic president — and do it in a very visible way,” said Martin Indyk, a vice president at the Brookings Institution and a former U.S. ambassador to Israel.

“There is no reason to schedule this speech before Israeli voters go to the polls on March 17 and choose their own leadership,” Kaine said in a statement Wednesday. “I am disappointed that, as of now, the speech has not been postponed. For this reason, I will not attend the speech.”

Kaine will join Senate colleagues Patrick J. Leahy (D-Vt.), Bernard Sanders (I-Vt.) and Brian Schatz (D-Hawaii) in skipping the address.

According to an unofficial estimate by one Senate Democrat, about 30 members of that caucus are expected to attend the speech and nearly 15 others are still deciding whether to boycott. One such Democrat is Sen. Chris Murphy (D-Conn.), a freshman who serves on the Foreign Relations Committee.

“It’s really offensive, but I think it’s a protocol breach, not a policy break,” he said.

Generally an ally of Israel, Murphy said his biggest concern was the spectacle occurring so close to the Israeli elections. “I don’t want to be part of a campaign speech,” he said. “It makes the whole thing look more politics-based.”

The American Israel Public Affairs Committee (AIPAC), which said it didn’t know about Netanyahu’s plans ahead of time, said lawmakers should put aside the protocol issues and listen to the prime minister’s message on the Iran talks.

Netanyahu was invited by Sens. Dianne Feinstein (D-Calif.) and Richard J. Durbin (D-Ill.) to attend a separate event with Democratic lawmakers, but he declined. In a letter, he said that it “could compound the misperception of partisanship regarding my upcoming visit.”

Sen. Orrin G. Hatch (R-Utah) said: “It’s unseemly what the Democrats have done to try and make this a political issue. I think the president has acted like an oaf, an oaf. O-a-f. . . . I don’t even want to get into it. I’m just mad.”

Meanwhile, leaked details about Iran nuclear negotiations have made many lawmakers more interested in what Netanyahu has to say.

“I think his voice will resonate more credibly if that’s the deal that’s in the making,” said Abraham Foxman, national director of the Anti-Defamation League. “Both the president and prime minister share the goal of preventing Iran from going nuclear. How to get there is what separates them.” Foxman initially called Netanyahu’s speech “ill-advised” but now says he will attend.

Sen. Jack Reed (D-R.I.), one of Obama’s strongest allies on the Hill, plans to attend Netanyahu’s speech. “I’m interested in what the prime minister is going to say,” Reed said. “I think it’s already been made an unnecessarily complicated political issue, but there is still this need to learn as much as we can about the situation.”

Many will hear Netanyahu on Monday, when he addresses the annual AIPAC convention. AIPAC expects 16,000 people to attend, including about 50 lawmakers.

Katie Zezima and Mike DeBonis in Washington and William Booth in Israel contributed to this report.