Iran indicates it has no plans to halt enrichment

The content of that response has not been made public and there was caution about the prospects of progress.

"It was not something that made us jump up and down for joy," said one European official, who spoke on condition of anonymity because the information was confidential. "We are in a holding mode until we get a chance to look at it more closely."

White House press secretary Dana Perino told reporters traveling with President Bush en route to a G-8 summit in Japan that the U.S. administration was still evaluating Iran's response.

"We're going out to consult with our allies about what Iran's response means," Perino said. "We'll just have to see how this is received by others before we make a formal response."

A positive response could open the way to renewed negotiations that might help cool recent sharp exchanges between officials on both sides. In recent weeks the U.S. and Iran have traded threats and warnings over possible American or Israeli military action.

But Iranian government spokesman Gholam Hossein Elham insisted Tehran would not change the central part of its controversial program. Uranium enrichment can produce either fuel for a nuclear reactor or the material for a warhead. Iran insists its enrichment work is intended to produce fuel for nuclear reactors that would generate electricity.

"Iran's stand regarding its peaceful nuclear program has not changed," Elham told reporters. He said Iran was ready to negotiate on its program "within the framework of the international rules and regulations."

He did not elaborate. But Iranian state media reported Friday that EU foreign policy chief Javier Solana and Iran's top nuclear negotiator, Saeed Jalili, have agreed to hold the latest in a series of talks in the second half of July.

The European official, however, said no firm decision will be made by Solana to meet with Jalili until the contents of the Iranian response had been evaluated.