The United States Wednesday dismissed as theatrical Iran's media tour of its Natanz nuclear facility. The State Department said if Iran wants to put to rest concerns about its nuclear intentions, it should fully cooperate with U.N. inspectors and European negotiators.

Officials here are making clear they are unimpressed by the media tour conducted by Iranian President Mohammad Khatami, who took some 50 Iranian and international journalists on a tour of the largely-underground Natanz facility south of Tehran.

Natanz has been a focus of concern for U.S. officials, who believe Iran's nominally-peaceful nuclear program is being used as cover for a secret weapons program.

Mr. Khatami showed reporters a vast, empty hall that Iranian officials said had been built to house some 50,000 uranium-enrichment centrifuges, but was inoperative because Iran had suspended enrichment activity.

A senior official who spoke to reporters here rejected any notion the media tour vindicated Iran's contention it is not seeking nuclear weapons, and called the exercise by President Khatami theatrical.

Briefing reporters, State Department Deputy Spokesman Adam Ereli said if Iran really wanted to allay suspicions about its intentions, it would let International Atomic Energy Agency (IAEA) inspectors enter what he called suspicious sites, and allow them to interview key officials associated with its nuclear program.

“I'm not going second-guess Iranian motives or intentions,” said Mr. Ereli.  “ will tell you that there are a large number of outstanding questions and concerns that the international community has long posed to Iran that Iran has not responded to fully. And that is the measure, I think, by which one should judge the Iranian commitment to transparency and consistency with international obligations, not press tours to sites.”

Mr. Ereli said the United States is on he same page with the British, French and German governments which have been trying to negotiate an agreement with Iran, offering incentives for its commitment to stop uranium enrichment activity.

The latest round of those talks ended last week in Vienna with no sign of movement, though Mr. Ereli declined to call the process deadlocked, saying it was up to the Europeans to make an assessment.

He said the United States and its European partners have a common approach and diplomacy, and that the choice for Iran is clear: to make a responsible decision on its nuclear program or find itself further isolated and further ostracized.

Iranian President Khatami told reporters Wednesday the Europeans were studying a compromise offer by Iran to limit its enrichment activity to 500 centrifuges, a fraction of the number considered necessary for bomb-making.

However spokesman Ereli said he did not think the assertion was credible. He said the United States and its allies remain united that only a complete halt to sensitive nuclear activities can provide the level of confidence they seek that Iran has abandoned its weapons program.