Top envoys for Iran and the European Union ended talks Thursday with little indication they were closer to resolving a deadlock over Tehran's refusal to suspend uranium enrichment.

Still, the two agreed to meet briefly again Friday and for a longer follow-up session within two weeks.

"Sometimes we are not able to move the process as we like, but in any case, the atmosphere continues to be very positive," said EU foreign policy chief Javier Solana after meeting with Ali Larijani, Iran's ranking nuclear negotiator.

Solana's comment appeared to be tacit acknowledgment that Iran refused to give way on international demands it suspend enrichment or face further U.N. Security Council sanctions.

Both Solana and Larijani said the main focus of their 4 1/2 hour talks were "outstanding issues" with the International Atomic Energy Agency. The IAEA has called on Tehran to clear up long-term questions it has about the Islamic republic's nuclear program.

An official familiar with the talks who refused to be identified because of their confidentiality suggested that meant Solana and Larijani decided to shift to less controversial ground because of lack of agreement on how to tackle the issue of enrichment suspension.

Larijani spoke of "some useful ideas that both sides introduced," and "common ground" without going into detail. Solana said he and Larijani had "an exchange of ideas on how to move the process" forward, and spoke of a "good atmosphere."

Both men said their aides would meet in about a week to prepare for another Solana-Larijani meeting in about two weeks' time. They also planned a brief session Friday.

With both Iran and the United States voicing hard-line positions ahead of Thursday's session, expectations were already muted before the two men began their discussions at a former hunting estate on the outskirts of Madrid.

Diplomats told The Associated Press that although Tehran recently suggested it was ready to discuss a partial suspension of enrichment, the West did not respond, and Iran has since withdrawn its offer.

Secretary of State Condoleezza Rice, speaking in Vienna, Austria, ahead of the Madrid talks, said the onus was on Iran.

"I think it's time for Iran to change its tactics," Rice said. If Iran does so, she said, "then we are prepared to ... sit with Iran and talk about whatever Iran would like to talk about.

"But that can't be done when Iran continues to pursue, to try to perfect technologies that are going to lead to a nuclear weapon," Rice said, alluding to the U.S. assertion that Tehran is seeking the cover of a peaceful nuclear program to make such arms.

Larijani, in comments to the Iranian state news agency before leaving for Spain, said: "Suspension is not the right solution for solving Iran's nuclear issue."

But Rice said Iran had no option but to "suspend, to demonstrate that it is in fact not seeking a nuclear weapon under cover of (a) civil nuclear power" program.

"The question isn't why won't we talk to Tehran; the question is why doesn't Tehran want to talk to us," she said.

A year ago, she reached out to Washington's longtime adversary with an offer to talk "any time, any place."

Iran did not accept Rice's offer for the first Cabinet-level direct talks in nearly three decades, because of the condition to halt enrichment.

There is a growing perception among some European nations that the five permanent U.N. Security Council nations plus Germany should drop their full suspension precondition for starting talks on a package of incentives. The powers are in the forefront of attempts to engage Iran.

At talks last month in Turkey, Larijani and Solana agreed to meet again to try to bridge the divide between Iran's insistence on its right to enrich and Security Council demands for a freeze.

Before that meeting, Iran suggested it was ready to stop some of its centrifuge machines, which can enrich uranium to the low level used to generate power and to high-grade material used in the fissile core of nuclear warheads, said one of the diplomats, who demanded anonymity for revealing confidential information.

But the U.S. and Security Council allies Britain and France continued to insist on full suspension, and another diplomat said that in Turkey, Larijani apparently changed tack, saying Iran was no longer interested in a partial and temporary suspension.

Although Iran insists it has the right to the technology to generate nuclear power, it has been hit with two sets of U.N. sanctions because of suspicions bred by nearly two decades of Tehran's clandestine nuclear activities that it wants atomic weapons.

Iran's ultimate stated goal is running 54,000 centrifuges to churn out enriched uranium for what it says is power generation. But critics say that equipment could also make enough fissile material for dozens of nuclear warheads a year.

The issue gained importance last week, when the IAEA sent a report to the Security Council that says Iran has expanded its enrichment activities instead of freezing them — a finding that could act as a trigger for a third set of sanctions.