KIRKUK, Iraq (Reuters) - Defense Secretary Robert Gates said on Friday he expected the international community to impose significant additional sanctions against Iran over its nuclear program.
A senior U.S. official said the United States and its allies would decide early next year whether to pursue more sanctions.
Gates also told U.S. troops in northern Iraq that military action against Iran would only delay its nuclear progress and instead urged a package of "incentives and disincentives" to convince leaders in Tehran to meet western demands.
He made his comments as European Union leaders meeting in Brussels expressed grave concerns about Iran's nuclear ambitions and also warned of new sanctions.
"I think you're going to see some significant additional sanctions imposed by the international community, assuming that the Iranians don't change course and agree to do the things they signed up to do at the beginning of October," Gates said.
Gates was referring to a deal under which Iran would have transferred stocks of low-enriched uranium (LEU) abroad, receiving fuel in return to run a reactor producing medical isotopes.
He said Iran was "stiffing" the international community by refusing to implement what was agreed in October.
That "has brought the international community, including the Russians and the Chinese, together in a way that they have not been in terms of significant additional sanctions on the Iranians," he said.
Western powers saw the deal as reducing Iran's scope to divert LEU for potential bomb-making, but Tehran later backed away from it.
In a statement, White House spokesman Robert Gibbs said the United States echoed the concerns expressed by European leaders and that Washington remained committed to finding a diplomatic solution.
"However, if Iran continues to fail to bring its nuclear program into full compliance with the requirements of the United Nations Security Council and the IAEA (International Atomic Energy Agency), there will be consequences and we will be consulting closely with our partners to ensure those consequences are credible," Gibbs said.
The United States, Britain and France warned Iran on Thursday that it may face new sanctions over its nuclear program, but Russia and China hinted that they were not convinced more punitive steps were needed.
The exchange of views during a U.N. Security Council debate on Iran showed how the Western powers' desire to ratchet up the pressure on a defiant Tehran over its atomic ambitions might face tough resistance from Moscow and Beijing.
The West suspects Iran of pursuing nuclear weapons. Iran rejects the allegations, along with U.N. demands that it suspend a program it says is intended solely for the peaceful generation of electricity.
Western officials say recent revelations about a previously hidden uranium enrichment plant in Iran have made Tehran's denials less credible.
Asked in a meeting with U.S. troops in Kirkuk about using military force to halt Iran's nuclear ambitions, Gates expressed skepticism over whether such action would work.
"Let me just say, you never take any options off the table. But the reality is that any military action would only buy some time, maybe two or three years," he said.
"So at the end of the day the way to avoid a nuclear-armed Iran is to put together a package of incentives and disincentives that persuade the Iranian government that they would actually be less secure with nuclear weapons than if they had them."
He added: "If we learned anything from Iraq over the past six years, it is the inherent unpredictability of war."
A U.S. official traveling with him on a five-day visit to Afghanistan and Iraq said a decision on sanctions would be made early in 2010.
"That's where we're heading," the official, speaking on condition of anonymity, said on Gates's plane.
In a draft statement expected to be approved at the meeting of EU leaders, they urged Iran to comply without delay with resolutions by the United Nations Security Council and the U.N.'s IAEA.
"Iran's persistent failure to meets its international obligations and Iran's apparent lack on interest in pursuing negotiations require a clear response, including through appropriate measures."
The term "appropriate measures" is used by the EU to refer to sanctions.
Additional reporting by Steve Holland in Washington; Writing by Ayla Jean Yackley; Editing by Michael Christie, Angus MacSwan and Paul Simao