By Patricia Zengerle
WASHINGTON, Jan 27 (Reuters) - An attempt to impose new sanctions on Iran over its nuclear program has stalled in the U.S. Congress and lawmakers are discussing whether to introduce a much weaker measure, congressional aides said on Monday.
Members of the Senate and House of Representatives are considering a non-binding resolution that expresses concern about Iran's nuclear ambitions and calls for negotiators to set strict conditions in talks between Tehran and world powers.
That would fall short of tightening sanctions on Iran, as envisioned in a bill that senators have been discussing for months.
"We don't think it is going to come to a vote," said a Senate aide who requested anonymity because that person was not authorized to speak to the media. "There are discussions about a resolution."
Iran has warned that it will walk away from talks on its nuclear program - raising the risk of conflict in the Middle East - if Congress passes a new sanctions bill.
Senate Democrats met recently and agreed not to push Majority Leader Harry Reid to bring the sanctions bill to the floor of the chamber, congressional aides said.
President Barack Obama's administration strongly opposed the sanctions bill, and threatened to veto it. The bill was co-sponsored by 59 of the 100 senators, including 16 of Obama's fellow Democrats.
Sources familiar with the Obama administration's thinking said the White House would object to a non-binding resolution at this stage in the delicate talks with Iran.
After reaching an interim deal last November, Iran and six world powers will likely hold the first round of talks on a long-term deal for Tehran next month at the United Nations in New York.
Tehran insists that its nuclear program is peaceful.
With no sign of movement on the Nuclear Weapon Free Iran Act of 2013 sanctions bill in the Senate, congressional hard-liners on Iran are shifting focus to the final, long-term agreement.
They want negotiators to demand the strictest restrictions possible, including insisting Iran give up all uranium enrichment, and dismantle - not just suspend - facilities including the Arak heavy water reactor, which could provide plutonium, an alternative to uranium for bombs.
"Here's the end game for me: I want the plutonium reactor dismantled, not frozen in place. I want the enrichment capabilities of the Iranians to be zero," Republican Senator Lindsey Graham of South Carolina told reporters recently.
"I want this administration to know that the Congress believes in dismantling, removing and stopping (Iran's nuclear program) and ... I think this administration has a completely different view of the endgame than I do," he said. (Editing by Alistair Bell and Amanda Kwan)