AP Photo/Iranian President's Office, File

TEL AVIV - Iranian negotiators are sitting down Saturday with officials from the five permanent members of the United Nations Security Council as well as Germany for the first talks about Iran's nuclear program since last January. The talks come as the west has imposed painful sanctions on the Iranian economy as they try to avert an Israeli military strike, whose leaders view a nuclear-armed Iran as an existential threat.

Iran has signaled it may be willing to make concessions in Saturday's so-called P5+1 - the United States, Russia, China, France, Great Britain and Germany - talks, but major progress is not expected.

"Iranian representatives will attend the talks with new initiatives," Iranian negotiator Saeed Jalili said before the talks, according to state IRNA news agency. "We are ready to hold successful and progressive talks on cooperation."

Of particular concern to the United States and Europe are Iran's new enrichment facility at Fordow, buried deep in a mountain, and Iran's enrichment of uranium up to 20%, just a few steps from weapons-grade which is 90%.

Last weekend, the head of Iran's nuclear program signaled it may be willing to drop enrichment to a lower level needed for power once it has enough 20 percent-enriched uranium stocked for its research reactor, which produces medical isotopes.

"I think nobody expects to resolve all differences in one meeting," deputy National Security Advisor Ben Rhodes told reporters on Air Force One on Friday. "What we want is a positive environment where the Iranian government demonstrates its seriousness and its commitment to pursuing serious negotiations with the P5+1."

"We want to begin with a negotiation that can address our concerns about their nuclear program and we want that negotiation to move forward with a sense of urgency."

Iran has long insisted it is not pursuing nuclear weapons, a claim not believed by the U.S. and Israel, which is the only nuclear-armed nation in the Middle East. Iran's supreme leader, Ayatollah Ali Khamenei, has even issued a fatwa - a religious edict - against pursuing nuclear weapons. In a Washington Post op-ed on Friday, Iran's foreign minister reiterated their peaceful intentions and blamed mistrust on the current atmosphere.

"To solve the nuclear issue, the scope of the upcoming talks between Iran and the P5+1 must be comprehensive," Ali Akbar Salehi wrote. "The concerns of all sides must be addressed. Complex matters that have been left unaddressed for decades cannot be solved overnight."

The P5+1 delegation is being led by the European Union's foreign policy chief Catherine Ashton. She met with Iranian negotiator Jalili on Friday night for a three-hour dinner in a "friendly atmosphere," a diplomat in Istanbul told Reuters.

"We want them to demonstrate, clearly, in the actions they propose that they have truly abandoned any nuclear weapons ambition," Secretary of State Hillary Clinton said on Thursday. "Of course, in a negotiation, we understand that the Iranians will be asking for assurances or actions from us and we will certainly take those under consideration."

Iran has bristled at what they called the west's "pre-conditions" before the talks, with President Mahmoud Ahmadinejad saying Thursday that "the Iranian nation is standing firm on its fundamental rights and under the harshest pressure will not retreat an iota from its undeniable right."

Israeli talk of a military strike against Iran's nuclear facilities has fueled strong American and European sanctions against Iran. But so far there has been no visible impact on Iran's nuclear program. The Israeli leadership has warned that the window before Iran reaches a "zone of immunity" - when a military nuclear program cannot be stopped - is rapidly approaching and says the talks are a stalling tactic.

A compromise in Turkey, including inspections of nuclear facilities by the International Atomic Energy Agency, could see the west relax its sanctions on Iranian financial institutions and its oil industry.

Iran has said that if Saturday's talks are productive, a second round could take place next month in Baghdad.