Binyamin Netanyahu, the Israeli prime minister, has responded to Barack Obama's call for an end to "loose talk of war" and bluster over Iran by reiterating Israel's "right to defend itself".
At the start of what appeared to be an uneasy meeting at the White House – at which Obama was expected to press the Israeli leader to stall any military action against Iran until sanctions have had an opportunity to persuade Tehran to open up its nuclear programme – Netanyahu did not waver from his insistence that he will decide whether to attack.
"When it comes to Israel's security, Israel has the sovereign right to make its own decisions. I believe that's why you appreciate, Mr President, that Israel must reserve the right to defend itself," he said.
"After all, that's the very purpose of the Jewish state, to restore to the Jewish people control over our destiny. And that's why my supreme responsibility as prime minister of Israel is to ensure that Israel remains the master of its fate."
Netanyahu arrived in Washington planning to press Obama to commit to military action against Iran if it crosses specified "red lines" in development of its nuclear programme, or if it fails to meet demands to dismantle its underground nuclear facility in Qom and halt uranium enrichment.
US officials say the president does not want to make any such commitment, even though he says the military option remains on the table, out of concern that it will be seen as implicitly endorsing an Israeli attack if the demands are not met.
Instead, Obama spoke of the "difficult months" ahead as he appealed for more time for sanctions to persuade Tehran to co-operate with international inspectors and demonstrate that it is not planning to build a nuclear bomb.
"It is profoundly in the United States' interest as well to prevent Iran from obtaining a nuclear weapon," Obama said. "That's why we have worked so diligently to set up the most crippling sanctions ever with respect to Iran. We do believe there is still a window that allows for a diplomatic resolution to this issue, but ultimately the Iranians' regime has to make a decision to move in that direction, a decision that they have not made thus far.
"My policy is prevention of Iran obtaining nuclear weapons … When I say all options are at the table, I mean it. Having said that, I know that both the prime minister and I prefer to resolve this diplomatically. We understand the costs of any military action."
The meeting follows Obama's speech on Sunday to America's powerful pro-Israel lobby group, the American Israel Public Affairs Committee (Aipac), in which he demanded an end to the "loose talk of war" and "bluster" against Iran – a clear reference to the noise coming out of Netanyahu's government.
The Israeli prime minister is to address Aipac on Monday evening.
Obama, who has repeatedly and defensively asserted his support for the Jewish state in recent days, also said he "has Israel's back" – a reassurance he repeated to Netanyahu at the White House.
"The bond between our two countries is unbreakable," he said. "Our commitment to the security of Israel is rock solid. And as I've said to the prime minister in every single one of our meetings, the United States will always have Israel's back when it comes to Israel's security."
Netanyahu, too, sought to emphasise the close ties, even while offering no reassurance to Obama – in public at least – that he is prepared to give sanctions the length of opportunity the US president would like.
"Americans know that Israel and the United States share common values, that we defend common interests, that we face common enemies. Iran's leaders know that, too. For them, you're the Great Satan, we're the Little Satan. For them, we are you and you're us. And you know something, Mr President – at least on this last point, I think they're right. We are you, and you are us," Netanyahu said.
The encounter was infused with some of the chill that has characterised the relationship since the pair first met as leaders three years ago and Obama mistakenly thought he could press Netanyahu into halting the construction of Jewish settlements in the West Bank – a major obstacle to serious peace talks with the Palestinians.
Last year, Netanyahu humiliated Obama by lecturing him in public at the White House on the Holocaust and Israel's history.
The two sides were clearly determined to paper over the differences on Iran as best they could, although a White House proposal to issue a joint statement of intent after the talks looked uncertain.
Tellingly, Obama made only a brief reference to the Palestinian issue and Netanyahu said nothing about it at all, demonstrating how much it has been sidelined by the Iran crisis, to the Israeli leadership's gratification.
The US president's speech to Aipac received a mixed reaction in Israel and the US.
Ayoub Kara, a deputy minister and member of Netanyahu's Likud party, criticised Obama over his warning against loose talk of war and bluster.
"There is a saying that it's easier to watch a fire from far away," he said.
"We, not the US, are facing an existential threat. If Israel doesn't bluster, the US will also be in danger, because Iran's missiles will reach them too. Israel is doing everything possible to keep the world safe, and it's unfortunate that the White House doesn't see things the way we see them here."
But the Israeli opposition leader, Tzipi Livni, blamed Netanyahu for deteriorating relations with Obama. "Relations between Israel and the US have become political during Netanyahu's term," she said.
"Netanyahu made Israel an issue in the American election and it's a mistake. Netanyahu must understand that relations with the US are an essential need. Our deterrence depends on it. He will be tested on whether he is able to draft the US into our interests or whether he will continue just manipulating internal American politics."
At the Aipac conference on Monday, the veteran but soon-to-be-ex senator Joe Lieberman said the choice as to whether military action is used is Iran's – but Lieberman was not shy of proposing the use of force.
"So far, though economic sanctions applied have clearly affected the Iranian economy, the fact is they haven't led the fanatics who today run that country to slow up their nuclear weapons programme one iota," he said.
"The Iranian regime must hear a message from us and we must state it loud and clear: either you peacefully negotiate an end to your illicit nuclear activities or they will be ended for you by military attack."
But opinion in Washington is divided. The Israeli leadership arrived in the city to be confronted by a full-page ad in the Washington Post signed by retired US generals and intelligence officers declaring: Mr President: Say No to War of Choice with Iran.
"Military action at this stage is not only unnecessary, it is dangerous – for the United States and for Israel," it says above the names of five former army and marine corps generals.
Much of the American public appears to agree. A Pew Research poll released on Monday said 51% of Americans want the US to stay neutral if Israel attacks Iran.