The United States says world powers are fully prepared to seek punitive action against Iran after it failed to provide a clear answer to their overture to Tehran to halt uranium enrichment and return to nuclear negotiations. Secretary of State Condoleezza Rice will discuss the issue Wednesday in Paris with her foreign minister counterparts from the permanent U.N. Security Council member countries and Germany.

Officials here say the next move in the nuclear confrontation will be up to the so-called P5 Plus 1 foreign ministers to decide in Paris.

But they are making clear the major powers are prepared to move ahead with the punitive side of their so-called carrots and sticks offer to Tehran in the absence of a clear response to the initiative.

Iran has had six weeks to consider the offer of incentives for it to suspend uranium enrichment and related activities, and return to negotiations with the European Union on its nuclear program.

What U.S. officials had hoped would be a decisive meeting between EU chief diplomat Javier Solana and Iranian nuclear negotiator Ali Larijani turned out to be inconclusive Tuesday in Brussels, with the Iranian envoy talking about ambiguities in the big-power proposal and the need for more talks.

A Solana spokesman described the Brussels meeting as disappointing.

At a news briefing, State Department Spokesman Sean McCormack reiterated that the Iranians have had plenty of time to consider a proposal that basically required them only to accept an enrichment freeze in order to avoid punitive action.

McCormack said he did not want to prejudge what Secretary Rice and her colleagues would decide, but insisted the six-powers are united in their intention to pursue penalties if Iran spurned the pathway of incentives and negotiations:

"There is a positive pathway that could lead to potential benefits to the Iranian people," he said. "That is the pathway of negotiation, and we are fully prepared to go down that pathway. We are also fully prepared, as are the other members of the P5 Plus 1 to go down the other pathway. That is the pathway of the U.N. Security Council. So in the absence of a clear answer, the P5 Plus 1 has in the past stated their willingness to go down that other pathway."

The spokesman said Secretary Rice got an initial telephone briefing from Solana on his talks with the Iranian envoy, and that the EU diplomat would provide a fuller assessment to the six foreign ministers Wednesday in the French capital..

The details of the six-power offer to Iran are still officially secret. But it is understood to include assistance for what Iran's nominally peaceful civilian nuclear program and other incentives to return to negotiations including spare parts for its U.S. aircraft.

The disincentives would begin a U.N. Security Council resolution against Iran that could be followed by various sanctions, either through the United Nations or by like-minded countries acting on their own.

Although Spokesman McCormack said there were no divisions among the P5 Plus 1 countries on their willingness to move to punitive action, there have been differences between the United States and its European allies on one hand, and Russia and China opposing U.N. sanctions on the other.

Despite Iranian denials, the United States has long maintained that Iran's nuclear program has a covert weapons component.