After three weeks of talks, the United States and key European countries remain locked in fundamental disagreement with Russia about the scope of U.N. sanctions that Iran should face for refusing to rein in its nuclear program.

The Europeans and Americans want tough sanctions to punish Iran but Russia says it will agree only to limited measures targeting the nuclear program. Neither side is budging, setting the stage for lengthy negotiations and the possibility of no immediate action against Iran.

Monitor the nuclear showdown in FOXNews.com's Iran Center.

U.S. Ambassador John Bolton said Wednesday that there were still "wide gaps" after six rounds of closed-door talks between the Russians and Europeans.

"We are still basically where we have been," said Bolton.

Russian Ambassador Vitaly Churkin echoed that view, saying that senior foreign ministry officials from the five veto-wielding U.N. Security Council members — the U.S., Russia, China, Britain and France — and Germany failed to bridge the differences during a telephone discussion Tuesday. He also said that there was "a rather intense exchange of opinion" at a Wednesday meeting of U.N. ambassadors.

Russia and China, who have major commercial ties with Iran, have been publicly pushing for dialogue instead of U.N. punishment, despite the collapse last month of a European Union attempt to entice Iran into negotiations.

In a comment showing his frustration with the deadlock, Bolton said Russia must understand that "the fight against nuclear proliferation is more important than commercial contracts."

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The Europeans circulated a draft resolution late last month that would order all countries to ban the supply of materials and technology that could contribute to Iran's nuclear and missile programs. It would also impose a travel ban and asset freeze on companies, individuals and organizations involved in those programs.

The draft would exempt a nuclear power plant being built by the Russians at Bushehr, Iran, but not the nuclear fuel needed for the reactor.

Russia proposed major changes that would limit sanctions solely to measures that would keep Iran from developing nuclear weapons and ballistic missiles. Russia would eliminate any travel ban, asset freeze, or mention of Bushehr.

The U.S. has proposed amendments that would strengthen the measures proposed by Britain and France.

Russian Foreign Minister Sergey Lavrov and Iran's top nuclear negotiator Ali Larijani called last week in Moscow for a renewal of international talks with Iran, rather than sanctions. Lavrov said Moscow could help bridge the differences with the U.S. and Europeans.

"After the discussions which we had with Mr. Larijani ... we believe that there is a chance for a negotiated outcome," Churkin said.

The six countries offered Iran a package of economic incentives and political rewards in June if it agreed to consider a long-term moratorium on enrichment and commit to a freeze on uranium enrichment before talks on its nuclear program.

But Iranian President Mahmoud Ahmadinejad has repeatedly and defiantly said his country would continue enrichment — which can produce either civilian nuclear fuel or fissile material for a warhead — and is not intimidated by the possibility of sanctions.

Bolton and Churkin, when asked whether negotiations should now move up to the level of the involved nations' foreign ministers, said the U.N. ambassadors would keep talking. But Bolton said other discussions would talk place, including on the sidelines of the upcoming Asia-Pacific summit in Vietnam, which will be attended by American, Russian and Chinese leaders.

In a Fox News interview Wednesday, Bolton expressed hope that President Bush and Russian President Vladimir Putin would talk about sanctions against Iran because "we've been having a lot of difficulty with Russia in particular."

U.S. National Security Adviser Stephen Hadley played down differences between Washington and Moscow, saying negotiations on U.N. resolutions are "a little bit like sausage-making."

"It's not pretty and a lot of it spills out to the public, but I think the international community has held together on this issue and I think it will again," he said.