US Defense Secretary Robert Gates expressed doubts Saturday that a deal was close on Iran's disputed nuclear programme, as the UN atomic chief said Tehran presented no new proposals at talks in Germany.

The comments come amid growing Western impatience with Iran for failing to respond clearly to a proposal for sending some of its uranium abroad for enrichment, amid fears Tehran may be trying to build a nuclear bomb.

"I don't have the sense we are close to an agreement," Gates said in Ankara, a day after Iranian Foreign Minister Manouchehr Mottaki said Tehran was "serious" about enriching uranium abroad and that a deal was near.

"If Iran has decided to accept the proposal of the P5-plus-one, they should do that to the IAEA (International Atomic Energy Agency)," he told reporters, referring to the five permanent UN Security Council members and Germany.

But IAEA director general Yukiya Amano, who met with Mottaki on the sidelines of the Munich Security Conference, said the Iranians brought nothing new to the talks.

"Our meeting covered a variety of areas. That included of course in Iran and the Tehran research reactor. We had a very interesting discussion.... There was not a new proposal. We exchanged views," Amano told reporters.

"Dialogue is continuing and should be accelerated, that is the point," he added.

Mottaki cast the talks with the UN nuclear watchdog in a positive light, calling it a "very good meeting".

"We discussed and exchanged views about a wide range of issues ... We also exchanged views about the proposal that is on the table. I tried to explain the views of the Islamic republic of Iran for the director general," Mottaki said.

Iran appeared to reject in October a deal proposed by the IAEA for Iran to export low-enriched uranium to France and Russia to be further purified into fuel for a research reactor in Tehran.

Enrichment outside of Iran is a central plank of a UN-brokered deal Western powers are pushing for out of fears that unsupervised enrichment could feed a covert nuclear weapons programme.

Enriched uranium produces fuel for a nuclear reactor but the process can also be used to make the fissile core of an atomic bomb.

Tehran insists its nuclear programme is strictly for civilian purposes.

Mottaki earlier told the conference that "with regard to discussions with the different parties, I personally believe that we have created conducive ground for such an exchange in the not very distant future."

He added that Iran "has shown it is serious about doing this, and we have shown it at the highest level," referring to President Mahmoud Ahmadinejad's assertion this week that Tehran would have "no problem" with the proposal.

Late Saturday, Iran's foreign ministry spokesman Ramin Mehmanparast said that if "the other side" shows a "realistic and positive approach and recognise our right they will definitely get a positive and appropriate response," he said, according to the Mehr new agency.

However, US and EU officials suspect the Iranian overture could be a delaying tactic to avert a fourth round of UN Security Council sanctions against the regime.

The US defense secretary said that Iran, if serious, should not waste time in accepting the proposal.

Iran has "done nothing to reassure the international community," Gates said, adding that "various nations need to think about whether it's time for a different tack."

Russian Foreign Minister Sergei Lavrov, whose country along with fellow Security Council member China is seen as less keen on more sanctions, urged Iran to work through the UN watchdog.

"What we want from Iran is to verify very specific questions, raised time and again by the IAEA a long time ago, it is not a difficult thing to do," he said in Munich.

Back in October Iran agreed in principle to the uranium enrichment offer but later appeared to reject it, saying it preferred a gradual swap of low-enriched uranium for fuel -- preferably on Iranian soil.

Tehran had given the West until January 31 to respond to its counter-proposals, and Iranian parliament speaker Ali Larijani again Saturday insisted that Western powers were trying to dupe Iran.

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