Netanyahu 'not correct' on Iran nuclear talks - Kerry
US Secretary of State John Kerry has questioned the judgement of Israeli PM Benjamin Netanyahu over his stance on Iran's nuclear programme.
Mr Netanyahu has criticised the US and others for "giving up" on trying to stop Iran obtaining nuclear weapons.
The Israeli PM "may not be correct", Mr Kerry said after attending the latest Iran nuclear talks in Geneva.
Mr Netanyahu will address Congress next week, after an invitation by Republican leaders criticised by the White House.
Mr Kerry was reacting to a speech in which Mr Netanyahu had said the US and others were "accepting that Iran will gradually, within a few years, develop capabilities to produce material for many nuclear weapons".
"I respect the White House and the president of the United States but on such a fateful matter, that can determine whether or not we survive, I must do everything to prevent such a great danger for Israel," he said in a speech in Israel.
Having just concluded the latest round of nuclear talks with Iran in Geneva, Mr Kerry told senators President Obama had made it clear the policy was not to let Iran get nuclear weapons and Mr Netanyahu's might therefore not be correct.
The invitation for Mr Netanyahu to speak before Congress has angered Democrats.
A spokesman for the White House warned against reducing US-Israeli relations to a party-political issue.
Analysis - Barbara Plett Usher, BBC News, Washington
Administration officials have been hitting back at Mr Netanyahu's aggressive opposition to the nuclear deal they're negotiating with Iran - they're unhappy his speech to Congress will give him a platform to make his case as talks reach a critical juncture.
Susan Rice's comments highlight that strain and are the most direct reference by a senior official to the damage caused by the controversy over the visit. It was arranged by Republican congressional leaders without consulting the Democrats or the White House, just two weeks before Mr Netanyahu faces an election.
That has angered Democrats, some of whom feel they'll be forced to choose between President Obama and their desire not to upset Israel. More than a dozen have said they plan to skip the speech, opening an unprecedented breach in the usual show of bipartisan support for Israel.
Earlier, US National Security Adviser Susan Rice had gone further and said Mr Netanyahu's visit was "destructive to the fabric of the relationship".
Mr Netanyahu was invited by House Speaker John Boehner in what is seen as a rebuke to US President Barack Obama's Iran policy.
Mr Netanyahu is expected to discuss Iran, as well as Islamist militant groups, in his address.
The current tensions took root over a decade ago when Iran's nuclear programme first came to light.
In 2005, Iran was referred to the UN Security Council, leading to a series of sanctions and UN resolutions requiring Tehran to stop enriching uranium.
The US and other powers - the so-called P5+1 - are negotiating with Iran on its nuclear programme. They want to agree a deal by March this year, but Mr Netanyahu is opposed to any agreement which might allow Tehran to retain the future capacity to build a nuclear weapon.
The Israeli leader has turned down an invitation to meet Senate Democrats privately, saying this "could compound the misperception of partisanship" surrounding his trip.
Media Analysis, BBC Monitoring
Israeli papers are divided over the Obama-Netanyahu spat, with one appearing bemused by the prime minister's stance.
"The odd, even tragic, thing is that Netanyahu has been doing all he can in recent weeks to help the Iranians achieve their goal," Hemi Shalev writes in Haaretz.
"First by alienating Obama and the administration, then by provoking the Democratic senators," he adds, referring to Mr Netanyahu's refusal to meet senate democrats separately.
A commentary in the pro-Netanyahu paper Yisrael Hayom comes out in strong support of the prime minister, saying his Congress speech will be "the last chance to prevent a bad agreement that leaves Iran a threshold nuclear state".
"The future will prove to what extent Israel was right to be at the forefront of the struggle against the US administration," Haim Shain writes.
In Yedioth Ahronoth, Guy Bechur dismisses fears of a deeper rupture between the US and Israel, and quotes a Gallop poll in the US as suggesting that 70% of Americans "support or very much support Israel".
Several Democratic members of Congress including Vice-President Joe Biden have said they will not attend the speech.
Republican leaders did not consult the Obama administration before inviting Mr Netanyahu, which the White House has called a breach of protocol.
White House spokesman Josh Earnest said on Wednesday: "The president has said the relationship between the US and Israel can't just be reduced to a relationship between the Republican party and the Likud party."
Mr Obama does not plan to meet Mr Netanyahu next week. The White House cited the "long-standing practice" of not meeting government leaders close to elections, which Israel will hold in mid-March.
Mr Netanyahu is fighting a tough election against the Labour Party's Yitzhak Herzog, who has focused on the prime minister's cooler relations with Mr Obama.