The United States expects a Security Council agreement on U.N. sanctions against Iran within weeks unless Tehran agrees at the last minute to freeze uranium enrichment, a senior State Department official said Friday.

Undersecretary of State Nicholas Burns also dismissed suggestions of cracks in the six-power coalition pushing Tehran to give up enrichment.

Speaking a day after those countries ended confidential discussions in Berlin, Burns said further talks were needed on how harshly to penalize Tehran for its refusal to freeze enrichment, as demanded by the Security Council. But he said a lot of progress was made.

Outlining the U.S. view of the timetable on Iran in the coming weeks, Burns said the six nations would further consult by phone on Monday and hoped to present a unified approach on sanctions to their foreign ministers by the time the U.N. General Assembly opens Tuesday.

"It's fair to say we have ... a lot more work to do," he told guests at an event staged by The American Academy in Berlin. "But I believe we will be successful in passing the sanctions resolution shortly" in the Security Council, he added.

CountryWatch: Iran

Thursday's meeting in Berlin came amid efforts by key European nations to enlist world support in pressuring Iran to give up uranium enrichment.

In a confidential document obtained by The Associated Press and sent to dozens of capitals last week, Britain, France and Germany warned that Tehran's stalling tactics on whether it was ready to meet terms for new nuclear talks were an attempt "to split the international community."

But there were indications that France, a key U.S. ally in pushing for firm U.N. action against Iran, might be wavering.

While Iran has expressed a desire for negotiations, the six nations have insisted that Iran suspend enrichment before talks begin. The six countries — Germany plus Security Council powers Britain, France, China, Russia and the U.S. — have offered Iran a package of economic, political and strategic rewards to comply with the demand.

But French Foreign Minister Philippe Douste-Blazy on Thursday appeared to suggest that demand was negotiable, telling reporters: "The question is to know at what moment this suspension takes place compared to negotiations."

Burns dismissed suggestions of a split, saying all five permanent Security Council members insist negotiations should not start until Iran suspends enrichment.

"I have not heard from any government from this group that we should change the basic offer, that hasn't changed," he said, adding: "No one mentioned anything like this" during Thursday's meeting.

"The Iranians are in a very tough position," Burns said. "At first they thought, let's divide the United States from the EU-3 and that didn't succeed. The Iranians are obviously trying to divide Russia and China from the rest of us, and that hasn't succeeded."

Still, a diplomat familiar with the U.S. stance said Burns was worried about the French statement, which would weaken what has been a unified stance between the four Western countries in the six-nation coalition for a need to move to sanctions if Iran remains defiant.

Burns spoke on the eve of a crucial meeting between senior EU envoy Javier Solana and Ali Larijani, the chief Iranian nuclear negotiator. An Iranian official told the AP the talks were set for Vienna, with Larijani scheduled to arrive Friday evening.

The talks are considered a final attempt to find common ground to start negotiations between Iran and the six powers.

As the Americans and their allies worked at the Berlin meeting to overcome Russian and Chinese opposition to sanctions, the European document appealed to other countries for support.

The 1 1/2 page paper labeled "In Confidence" summarizes Iran's response to incentives package. The six powers have also asked Iran to consider a long-term moratorium on the technology, which can be misused to make nuclear arms.

Iran, which insists its nuclear program is meant only to produce fuel, refused suspend enrichment by an Aug. 31 deadline set by the Security Council. Its Aug. 22 response to the rewards offer has been kept confidential. But the United States and its allies have described it as unsatisfactory, primarily because of Tehran's refusal to consider freezing enrichment.

"The Iranian goal obviously is to split the international community," says the document, drawn up by Britain, France and Germany. While not specifically threatening U.N. sanctions, it says the Security Council will have to consider "further steps" if Tehran continues to defy the council.

Diplomats familiar with the document said it was drawn up to inform other nations of the substance of Iran's counteroffer and share the Western view that it was inadequate.

"The reply is along the lines of previous Iranian statements in that typically it neither accepts nor rejects outright" the six-nation proposal, said the document.