Israeli Prime Minister Benjamin Netanyahu warned Monday Iran must dismantle its "military nuclear program" as a condition for a diplomatic breakthrough that would head off the prospect of military action.

Netanyahu told President Barack Obama in White House talks that such a step was Israel's "bottom line" as hopes rise of a deal to end the nuclear showdown between Washington, world powers and Tehran.

Obama, meanwhile, promised Netanyahu that the United States would be "clear eyed" in talks with Iran but that it had to "test" prospects for a breakthrough, though reserved the right to take military action against nuclear installations in Iran if diplomacy failed.

Netanyahu warned that Iran was committed to Israel's destruction and that its words and actions should be judged with that in mind.

"The bottom line is that Iran fully dismantles its military nuclear program," he said after over an hour of talks with Obama in the Oval Office.

Netanyahu also argued that economic sanctions must be kept in force through any diplomatic process with Iran, which will resume next month in Geneva.

"Those pressures must be kept in place," he said.

"In fact, if Iran continues to advance its nuclear program during negotiations, the sanctions should be strengthened."

Obama credited the economic sanctions that have hammered Iran's economy with prompting its leaders to try a more serious diplomatic process on the nuclear program, following his telephone call on Friday with Iranian President Hassan Rouhani.

"We have to test diplomacy, we have to see if in fact they are serious about their willingness to abide by international norms and international law," Obama said.

"We enter into these negotiations very clear eyed. They will not be easy."

Obama also made clear that he reserved the right to take military action against Iran.

"We take no options off the table, including military options," Obama said.

EU plays down deadline for Iran talks
Washington (AFP) Sept 30, 2013 - EU foreign policy chief Catherine Ashton on Monday played down Iran's calls for a nuclear accord within a year, saying that technical work will take time.

Iran's new moderate leadership said last week that major powers had agreed to seek a deal within 12 months on Tehran's disputed nuclear program after landmark contact between the Islamic republic and the United States.

Ashton, who will lead the October 15-16 negotiations in Geneva among Iran and six other nations, said that the potential dismantling of parts of Tehran's nuclear program required expertise "and that technical work takes time."

"Part of being level-headed, clear-eyed, is to say, okay, if this is real, let's make it real and let's make sure that everybody can be confident in what we're actually doing," Ashton said in Washington when asked about the timeframe for a deal.

Ashton said it was critical to convince "those who are most worried and most skeptical."

Iran's newly elected President Hassan Rouhani on Friday spoke by telephone to his US counterpart Barack Obama, the first contact between the nations' leaders since the 1979 Islamic Revolution.

Obama met Monday with Israeli Prime Minister Benjamin Netanyahu, who has denounced Rouhani as an imposter and demanded that sanctions be maintained or strengthened.

"By no means is the prime minister of Israel alone. There are plenty of those who have good reason to be concerned, either because of proximity or because of things that have been said historically," Ashton said at the Woodrow Wilson International Center for Scholars.

Iran's former president Mahmoud Ahmadinejad was known for his strident denunciations of Israel and his denial of the Holocaust.

Rouhani has toned down Iran's criticism of Israel, while urging Obama to ignore "warmongering pressure groups."

Days before his inauguration, the House of Representatives easily approved a proposal to stiffen already tough sanctions that have inflicted pain on Iran's economy.

Ashton, asked about the US sanctions bill which also enjoys wide support in the Senate, declined to criticize the move overtly but called on all sides to work for progress.

"I would like to get to Geneva with the best possible atmosphere to have these negotiations," she said.

"That means, in all sorts of ways, we need to show willingness and good faith to sit down and talk and expect the same in return," she said.

"We keep the pressure on, but the pressure is there for a reason. It's to bring people to the talks in order to try and make progress," she said.

Ashton said that the Geneva talks would be held at the level of senior diplomats rather than political leaders, with the United States to be represented by Under Secretary of State Wendy Sherman.

The other nations in the talks are Britain, China, France, Germany and Russia, along with Iran itself.