Iran confirms that it is enriching uranium, but insists that the process is going forward on a very small scale. Word of Iran's nuclear activities came as Russia, France and the United States called on Tehran to halt the program.

The head of Iran's nuclear program, Gholamreza Aghazadeh, says uranium enrichment at the country's Natanz facility south of Tehran is limited to research and involves just a few centrifuges. He says the program is not on an industrial scale, and that several months would be required to utilize all of the 164 centrifuges the country possesses.

Centrifuges are used to generate nuclear material that could either be used in reactors to generate energy, or to build atomic weapons.

But assurances from Tehran are not assuaging Western apprehensions. In a joint declaration in Moscow, Russian President Vladimir Putin and French Foreign Minister Dominique de Villepin called on Iran to halt all activities linked to uranium enrichment and to cooperate fully with the International Atomic Energy Agency. Separately, Germany urged maintaining the cohesion of the international community with regards to Iran's nuclear ambitions, while China urged all sides to show restraint.

Iran has long insisted it only wants to provide for the energy needs of its growing population.

In Washington, White House spokesman Scott McClellan said the international community cannot take Iran at its word. "It is an issue of trust. The regime in Iran has shown that it cannot be trusted. For two decades, it hid its activities from the international community. It did not follow its safeguard obligations. And the International Atomic Energy Agency spelled out very clearly what Iran needs to do. It also referred the matter to the United Nations Security Council. Now Iran has an opportunity to respond to what was passed by the [I.A.E.A.] board of governors," he said.

McClellan added that it is time for Iran to cooperate in good faith rather than play games with the international community.

At the U.S. Congress, Republican Senator Sam Brownback of Kansas said the United States must not be afraid to restrict access to the U.S. market for nations that refuse to take a tough stand against Iran's nuclear activities.

"Both Russia and China need international technological and management support to keep their activities going, not the least of which is access to the U.S. marketplace. And no international company is going to treat lightly exclusion from the U.S. market in exchange for a contract with the Iranian government."

The Senator said the United States must maintain a strong military and make a concerted push towards energy independence.