WASHINGTON - John Kerry warned Benjamin Netanyahu on Monday not to endanger US nuclear talks with Iran by revealing details of the discussions, as the Israeli premier lobbied in Washington to thwart the deal.
The US Secretary of State issued his warning from the scene of the talks in Geneva, as the Israeli prime minister prepared to make a speech to the powerful pro-Israel AIPAC lobby.
Netanyahu has infuriated the White House and Democratic lawmakers by accepting an invitation by President Barack Obama's Republican foes to speak on Capitol Hill Tuesday.
Kerry intervened in the row after becoming "concerned by reports" that "selective details" of the deal aimed at curbing Tehran's nuclear programme would be revealed in the coming days.
He did not mention Netanyahu by name, but attempted once again to defend his talks in Switzerland with his Iranian counterpart Mohammad Javad Zarif.
"The best way to deal with the question surrounding this nuclear programme is to find a comprehensive deal, but not a deal which comes at any costs," he told reporters.
"We have made some progress, but we still have a long way to go, and the clock is ticking." Obama's administration has mobilized to counter Netanyahu's diplomatic offensive.
Washington's United Nations envoy Samantha Power and National Security Advisor Susan Rice, will also address the 16,000 AIPAC delegates.
A member of Netanyahu's entourage told journalists traveling with him on Sunday that the Israeli leader had not intended to offend Obama.
"We are trying to explain to the Americans what is causing us concern," he said, speaking on condition of anonymity.
"We know a great deal about the emerging agreement... In our view, it is a bad agreement." The official would not indicate the source of the "excellent information" Israelis have about the deal between the Islamic republic and the so-called P5+1 group that would prevent Tehran from developing a nuclear bomb.
But he said Netanyahu would elaborate in his congressional address.
Israel worries that Iran and world powers will likely clinch a deal that eases sanctions without applying sufficiently stringent safeguards.
In return for Tehran's agreement, the West would ease punishing sanctions imposed over its nuclear programme, which Iran insists is purely civilian.
Deal deadline 'not sacred'
Netanyahu's trip comes just four weeks before a March 31 target for a framework deal with Iran. Negotiators intend to pin down the technical details of a comprehensive agreement by June 30.
The Israeli official suggested that if a satisfactory agreement cannot be achieved within that timeframe, talks should be extended.
"The date is not sacred," he said.
In past visits to Washington, Netanyahu has warned in chilling terms of the threat to Israel that a nuclear-armed Islamic republic would pose, comparing it to the Nazi Holocaust of European Jews.
Educated at the Massachusetts Institute of Technology and Harvard University, before joining the prestigious Boston Consulting Group, Netanyahu revels in his knowledge of American idioms when addressing US audiences.
In a widely-quoted 2012 speech he said that Iran's construction of underground nuclear facilities and development of intercontinental ballistic missiles (ICBMs) belies its assertion that its nuclear programme serves only peaceful purposes.
"If it looks like a duck, walks like a duck, and quacks like a duck, then what is it?" he asked the conference then.
"It's a duck. But this duck is a nuclear duck. And it's time the world started calling a duck a duck." Last year, he played on a Budweiser beer advert to warn of danger from Iranian Scud missiles.
"You remember that beer commercial, 'This Bud's for you?' Well, when you see Iran building ICBMs, just remember, America, that Scud's for you." Obama has refused to meet Netanyahu during his visit, and Vice President Joe Biden and Secretary of State John Kerry will both be abroad.