TEHRAN, Iran — U.S. Secretary of State Condoleezza Rice on Monday dismissed Iran's recent response to a proposed solution over its nuclear program in Geneva over the weekend as "small talk" meant to buy time. She warned that new sanctions would be forthcoming if Iran did not comply with international demands to halt or slow its production of enriched uranium.

Rice, speaking to reporters in Ireland, said U.S., European and U.N. Security Council sanctions on Iran's energy and banking sectors would be heightened if Iran did not agree to stop expanding its production of enriched uranium, which can be used to produce electricity or, if highly enriched, fissile material for a bomb.

The Bush administration broke with its long-standing policy of refusing to engage with Iran until it halts enrichment by dispatching Undersecretary of State William J. Burns to the Geneva talks.

At the meeting, Iran did not give a yes-or-no answer to the proposed "freeze-for-freeze" option in which world powers would stop pressing for new sanctions during a six-week period of pre-negotiations if Iran agreed to stop adding new uranium-enriching centrifuges during the same period of time.

Flustered American, European, Russian and Chinese diplomats gave Iran a two-week deadline to respond positively to the offer or face economic sanctions as early as late August.

"We are in the strongest possible position to demonstrate that if Iran does not act then it is time to go back to that track," Rice was quoted as saying about sanctions. "The main thing is we will have to start considering what we do in New York," she said, referring to the home of the United Nations and the Security Council.

Rice's comments were the harshest yet about the meeting Saturday and could push energy prices higher on worries of increased tensions in the oil-rich Persian Gulf. U.S., Israeli and Iranian officials have painted dire scenarios if the crisis over Iran's nuclear program escalates to a military confrontation. Rice was on her way to the gulf to meet with Burns and leaders of pro-U.S. Arab officials to discuss Iran.

Iranian nuclear negotiator Saeed Jalili, who represented Iran at Saturday's talks, gave a more upbeat assessment of the meeting as he arrived in the Iranian capital Monday. He said no one pressed Iran on suspension and played down the two-week deadline.

"What happened in Geneva was some discussions about the two sides' approaches to the nuclear talks and their timing," he told reporters, according to the official Islamic Republic News Agency.

On Sunday, Iranian president Mahmoud Ahmadinejad described the meeting as a success. "Any negotiation that takes place is a step forward," Ahmadinejad told reporters, according to IRNA. "Yesterday's negotiation is regarded as one of these forward-moving negotiations."

But Rice drew a gloomier picture. She called Jalili's lengthy presentation "meandering" and frustrating to all the diplomats present.

"We expected to hear an answer from the Iranians but, as has been the case so many times with the Iranians, what came through was not serious," she told reporters.

"It's time for the Iranians to give a serious answer," she said. "They can't go and stall and make small talk about culture, they have to make a decision. People are tired of the Iranians and their stalling tactics."