By Lesley Wroughton
WASHINGTON (Reuters) - U.S. Secretary of State John Kerry on Monday pressed Iran to finalize an agreement that can prove to the world its nuclear program is peaceful, but said he has "no specific expectations" for talks in Geneva this week between major powers and Iran.
The White House said President Barack Obama will meet with Senate leaders on Tuesday to press his case that lawmakers should not adopt any further economic sanctions on Iran over its nuclear program to allow the international talks a chance to succeed.
Last week, a senior U.S. official said the six major powers and Iran were getting closer to an initial agreement, but Kerry appeared to tamp down expectations two days before talks resume.
"I have no specific expectations with respect to the negotiation in Geneva except that we will negotiate in good faith and we will try to get a first-step agreement," Kerry told a news conference with Turkish Foreign Minister Ahmet Davutoglu.
Kerry said he hoped that "Iran will understand the importance of coming there prepared to create a document that can prove to the world this is a peaceful program."
"I am not going to negotiate this in public. We all need to be respectful of each others' processes here and positions - and so it's best to leave that negotiation to the negotiating table," he added, declining to discuss details of a proposal under discussion.
The six world powers are negotiating a proposal that would ease sanctions on Iran if it suspends some parts of a program that many countries, particularly in the West, fear is aimed at developing a nuclear weapons capability.
The talks between Iran and the so-called P5+1 powers, comprising the United States, Britain, China, France, Germany and Russia, resume in Geneva on Wednesday. They will try to reach a first-step agreement to end a 10-year deadlock over Iran's nuclear program.
Iran has denied that it wants to develop an atomic weapons capability and insists its nuclear ambitions are limited to the peaceful generation of electricity and other civilian uses.
State Department spokeswoman Jen Psaki said Kerry is open to participating in the upcoming talks "only if it makes sense" but will not decide until the talks get underway.
Talks between the P5+1 and Iran ended last week without an agreement, although the sides appeared to be close to a deal.
CONGRESSIONAL ACTION ON SANCTIONS
Obama urged Congress last week to hold off on new sanctions and sought to reassure lawmakers that any easing under the proposed deal would be modest and could be quickly reversed if Iran shows it is not serious about curbing its nuclear program.
The president plans to make that case again to lawmakers when he meets them at the White House, presidential spokesman Jay Carney said on Monday.
"When it comes to our position on additional sanctions, I'm sure that this will be a topic because it's the president's view that it's the right thing for Congress to do to pause so that we can test whether or not the Iranians are serious about resolving this issue diplomatically," Carney told reporters.
Legislation to impose tough new sanctions on Iran is not expected to come to a vote in the Senate before December, U.S. lawmakers and congressional aides said.
Some Republicans have said they were considering proposing new sanctions on Iran as an amendment to a defense authorization bill the Senate is debating this week.
But lawmakers and aides said no such action was expected until after senators come back on December 2 from next week's Thanksgiving recess.
"I don't see anything happening until we get back," Senator Bob Corker, the top Republican on the Senate Foreign Relations Committee, told reporters.
The U.S. push for an agreement has stoked tensions with American ally Israel, which wants tougher U.S. sanctions against Tehran to force it to completely dismantle its nuclear program.
Kerry said he had "great respect" for concerns by Israeli Prime Minister Benjamin Netanyahu about a deal with Iran but did not believe the talks would put Israel's security at any additional risk.
"Nothing that we are doing here, in my judgment, will put Israel at any additional risk - in fact, we believe it reduces risk," Kerry said. "We believe it helps all of us move closer to this goal of achieving a comprehensive agreement."
Kerry said he was committed to returning to Israel after the Thanksgiving holiday to continue talks with Netanyahu over Iran and ongoing Israeli-Palestinian peace talks.
"That is a priority for me and it doesn't change," Kerry said. "We remain deeply committed to this ongoing dialogue, to our friendship, and we intend to consult frequently and deeply about everything we are engaged in."
(Additional reporting by Patricia Zengerle, Roberta Rampton and Mark Felsenthal; Editing by Will Dunham)