TEHRAN, Iran -- Iran indicated Saturday that it has no plans to meet a key Western demand that it stop enriching uranium, a day after Tehran sent the European Union a response to an international offer of incentives for halting enrichment.

The content of that response has not been made public and European officials declined to comment on it Saturday, but 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."

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 an Iranian government spokesman insisted that 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," Gholam Hossein Elham said.

Elham also 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.

Iran's ambassador to Belgium presented the response to the package to Solana in Brussels, Iranian state media reported Friday. European officials said they were studying the Iranian response and were consulting among themselves and with the United States, Russia and China on what to do next.

Acting on behalf of the five permanent members of the U.N. Security Council and Germany, Solana offered the modified package of economic incentives to Iran during his June visit to the country. The offer is meant to persuade Iran to halt enrichment.