The lead negotiator for the six-nation group bargaining with Iran over its contentious uranium enrichment program said Friday that she hoped to achieve “the beginnings of the end” of the dispute at the next meeting, to be held in Baghdad on May 23.

The negotiator, Catherine Ashton, the European Union’s foreign policy chief, did not offer specifics about the substance of the next meeting, the second since Iran and the so-called P5-plus-1 nations — the five permanent members of the United Nations Security Council plus Germany — announced on April 1 that they were resuming discussions after a lapse of more than a year. Both sides described the first meeting in Istanbul on April 13 and 14 as constructive.

Western powers suspect that Iran is enriching uranium as part of an effort to achieve the ability to make nuclear weapons. Iran has insisted that its enrichment is for peaceful purposes and has defied Security Council demands that it suspend the program. The dispute has escalated tensions in the Middle East and raised fears that Iran’s nuclear facilities would be attacked by Israel, which regards Iran as its top enemy. But the belligerent-sounding rhetoric has quieted somewhat with the resumption of talks.

Ms. Ashton made the statement about the negotiations in response to question at a news briefing in Brussels, after she had signed a European Union cooperation agreement with her Iraqi counterpart, Foreign Minister Hoshyar Zebari.

”My ambition is that we come away with the beginnings of the end, if you like, of the nuclear weapons program in Iran,” she told reporters. “I approach this with great seriousness, with great determination, and I hope that we’ll see the beginnings of success.”

Mr. Zebari, who was thanked by Ms. Ashton for having arranged to act as host for the negotiations, studiously avoided taking sides in the dispute in his comments to reporters. “Iraq,” he said, “ has a vested interested in success of these talks.”

In Vienna, where the International Atomic Energy Agency, the United Nations nuclear monitor, was concluding a meeting on nonproliferation on Friday, Iran’s delegation reiterated its intention to continue uranium enrichment, Iran’s official Islamic Republic News Agency reported. It quoted Iran’s ambassador to the agency, Ali-Asghar Soltaniyeh, as saying Iran was perfectly within its legal rights.

An I.A.E.A. report on Iran’s enrichment activities last November raised questions about some Iranian behavior that suggested that it had been working on military applications. Inspectors with the agency have been denied permission to visit the Iranian military site known as Parchin, where, they have said, they think Iran may have conducted nuclear bomb trigger experiments. Last week, the I.A.E.A. director general, Yukiya Amano, said gaining access to Parchin would be its priority at a meeting with Iranian officials in Vienna next Monday and Tuesday.

Earlier this week, the Institute for Science and International Security, a Washington-based group that tracks nuclear proliferation, released new commercial satellite imagery of Parchin that it said suggested that the Iranians had sought to clean up a suspected explosives testing chamber there.

Iran’s Foreign Ministry has since ridiculed the group’s assessment, the semiofficial Mehr News Agency reported Friday. It quoted the ministry’s spokesman, Ramin Mehmanparast, as saying:“The institute is not experienced enough. If it was, it would know that nuclear activities cannot be cleaned up in such a way that they claim, and they have joked with our nation.” (Copyright 2012 The New York Times Company 05/12/12)