WASHINGTON - Israeli Prime Minister Benjamin Netanyahu arrived in Washington on Sunday for a "historic" quest to stop a "bad" international nuclear deal with Iran sought by the United States.
Netanyahu's controversial 48-hour visit has stoked discord with US President Barack Obama and brought bilateral relations to their lowest point in years.
A speech before lawmakers on Tuesday by the Israeli leader aims to drum up last-minute support to halt a possible world deal with Iran over its nuclear programme.
It has infuriated the White House and prominent Democrats because the speech was set up by congressional Republicans without consulting with the president, violating usual protocol.
Several leading members of America's political establishment have announced they plan to skip the address to a joint session of the US Congress.
And no meetings have been set up between Netanyahu and US government officials during his visit.
"We know a great deal about the emerging agreement," a member of Netanyahu's entourage said on condition of anonymity.
"In our view, it is a bad agreement." He 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.
In return, the West would ease punishing sanctions imposed on Tehran over its nuclear programme, which Iran insists is purely civilian.
For his part, Netanyahu, who will also speak at the annual policy conference of the powerful pro-Israel AIPAC lobby, has refused to back down.
"I'm going to Washington on a fateful, even historic, mission," he told reporters on the tarmac at Ben Gurion airport near Tel Aviv shortly before his plane took off.
"I feel deep and sincere concern for the security of Israel's citizens and for the fate of the state and of all our people," he added.
"I will do everything in my power to ensure our future."
Kerry: US, Israel 'closer than ever'
Secretary of State John Kerry - who will be leaving Washington at almost exactly the same time Netanyahu is arriving - insisted the United States is eager to avoid politicizing the controversial visit.
"The prime minister of Israel is welcome to speak in the United States obviously and we have a closer relationship with Israel right now in terms of security than in any time in history," Kerry told ABC television's "This Week" programme.
"We don't want to see this turned into some great political football." Meanwhile, Netanyahu's allies in Congress were as outspoken as ever, insisting that Obama, not the Israeli leader, was to blame for the recent discord.
"What I do wonder is why the White House feels threatened because the Congress wants to support Israel and wants to hear what a trusted ally has to say," John Boehner, the speaker of the House of Representatives, told CBS's "Face the Nation." Israel worries that Iran and world powers will likely clinch a deal that eases international sanctions on Tehran without applying sufficiently stringent safeguards to halt its nuclear drive.
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 next round of talks is due to begin next week in Switzerland.
Netanyahu's visit also comes about two weeks before a March 17 general election in Israel in which he is hoping to win a third consecutive term in office.
Kerry suggested there were no hard feelings, despite the administration's ruffled feathers after the speech was announced.
"Obviously, it was odd if not unique that we learned of it from the speaker of the House (Boehner) and that the administration was not included in the process, but the administration is not seeking to politicize this," Kerry said.
"We want to recognise the main goal here is to prevent Iran from getting a nuclear weapon, and on that, Israel and the United States agree." The top US diplomat stressed that the two allies have an "unparalleled close security relationship." Those mollifying words were far gentler than remarks from the Obama administration just days ago, when the president's National Security Advisor Susan Rice warned that the Netanyahu speech would be "destructive of the fabric of the relationship." US Vice President Joe Biden, who normally would be expected to preside over such an important ceremonial joint congressional session, also found pressing overseas business that he said would prevent him from attending Netanyahu's address.
Kerry has said that a week of overseas travel also will keep him away from the speech.