President Barack Obama said Sunday that "time is running out" for Iran to sign on to a deal to ship its enriched uranium out of the country for further processing, and Russian President Dmitry Medvedev said he still hopes to persuade Iran to send its enriched uranium to his country.
If that plan fails, however, Medvedev said other options remain on the table. While he did not cite those options, the Russian leader has said further sanctions against Iran were possible if it did not open its nuclear program to inspections to prove it was not trying to build a bomb.
Obama and Medvedev, meeting on the sidelines of the Asia-Pacific Cooperation Council, said Iran was one of the topics they discussed.
"Unfortunately, so far at least, Iran appears to have been unable to say yes to what everyone acknowledges is a creative and constructive approach," Obama said. "We are now running out of time with respect to that approach."
Russia and the U.S. are among six nations leading an effort to ensure Iran does not use what it maintains is a civilian nuclear program to develop an atomic bomb. But Moscow also has close ties with Iran and is helping build its first nuclear power plant, forcing Russia into a delicate balancing act.
Fears about the nature of Iran's nuclear program were heightened in September with the disclosure of a uranium enrichment facility near the holy city of Qom. U.N. inspectors visited the site last month, as the United States continued quiet preparations for the possibility of stiffening U.N. sanctions or those the United States has applied on its own.
Iran agreed to the inspections during a landmark meeting with the U.S. and other world powers at the beginning of October in Geneva, where the idea of Tehran shipping uranium to Russia for further enrichment was first raised.
Under the plan, Iran would send 2,420 pounds of low-enriched uranium to Russia in one batch by the end of the year in order to receive the nuclear fuel it needs for a research reactor that makes medical isotopes.
The United States supports such peaceful or beneficial uses of nuclear technology in Iran but has long suspected that part of the Iranian nuclear development program is aimed at covert production of a weapon.
The isotopes arrangement is a way to buy time and build confidence on both sides. By Western estimates, the plan would take put amounts of the low-enriched uranium Iran has stockpiled out of reach for conversion into the highly enriched fuel needed for nuclear weapons.
The arrangement is not a guarantee that Iran could not develop a bomb if it chose to, but is thought to delay the likelihood of that breakthrough. The deal would be the most tangible payoff for Obama's program of careful outreach to Iran this year, a diplomatic overture dimmer by political violence and alleged vote-rigging in Iran's elections last June.
Iran's diffuse political power structure has been in disarray since the election and the unprecedented street protests that followed. Squeezed by dissent inside the country and by international pressure over the nuclear program from outside, Iran has given conflicting signals.
Iranian politicians have rejected the proposed deal but the government says it is still considering it.
"The recent actions of this country (U.S.), presenting unimportant and irrational proposals in the nuclear issue which they have called just and fair, all indicate that the alleged change was nothing but a deceitful symbol aimed at deceiving naive politicians," Parliament Speaker Ali Larijani said Sunday in Iran.
Obama said he and Medvedev agree that the U.S. and Russia will continue to urge Iran "to take the path that leads them to meeting its international obligations."
Obama added, "We can't count on that, and we will begin to discuss and prepare for these other pathways."
Medvedev said the U.S. and Russia are not satisfied with the pace of the effort and reiterated Obama's point about reaching an end to it.
"In this case, our goal is clear: It is transparent, up-to-date, peaceful program _ not a program that would raise questions or concerns from the international community. We're prepared to work further and I hope that our joint work will yield in positive results," he said. "In case we fail, the other options remain on the table in order to move the process in a different direction."
Mike McFaul, an official with the White House National Security Council, told reporters at a briefing in Singapore that a timetable for sanctions against Iran was not discussed.
The administration prefers international sanctions if Iran balks but also quietly supports legislation in Congress that would give Obama a broad new array of authority to target Iran's energy sector by penalizing foreign firms that sell and ship refined petroleum products to Iran. The regime is heavily dependent on gasoline, kerosene and propane imports.
The legislation would also allow the administration to go after insurance and reinsurance concerns that cover oil tankers and their cargo. The U.S. could also target companies that provide Iran with covert technology used to crack down on protesters and democracy advocates as it did during demonstrations last summer after a disputed national election.
AP National Security Writer Anne Gearan contributed to this report.
(This version CORRECTS the timing of U.N. inspection.)