"Obviously we would be concerned if it seemed Iran was proposing a long delay," a spokesman for the office said on customary condition of anonymity. "We hope their willingness to take the diplomatic route will become clear soon."

The premier of China - a close ally of Tehran who has opposed talk of possible UN sanctions - said Iran must earn international trust over the nature and scope of its nuclear program.

"As things stand now, Iran needs to use real actions to win the confidence of the international community," Wen Jiabao said during a visit to South Africa.

Iranian Foreign Minister Manouchehr Mottaki, in Rome for talks, said that Bush "should not be in a hurry" for a response from Tehran. Mottaki said "no deadline was agreed upon" when the Europeans presented the proposal to Iran on June 6.

The package put forward by the five permanent UN Security Council members plus Germany seeks to persuade Tehran to suspend uranium enrichment in return for incentives including significant concessions by the United States. The US would provide Iran with peaceful nuclear technology, lift some sanctions and join direct negotiations with Tehran.

Enrichment can produce either fuel for a nuclear reactor or fissile material for a warhead. Iran says it is pursuing peaceful energy generation. The United States and some Europeans accuse Iran of seeking to develop nuclear weapons.

The package also pulls back from demands that Iran scrap enrichment outright and permanently, seeking only a suspension instead. It contains the implicit threat of UN¡¡sanctions if Iran rejects the package.

Iranian officials have been sending mixed signals since receiving the proposals. They have issued tough vows never to surrender their "right" to enrich uranium. But they have not directly rejected a suspension - and have said they see some good and some bad in the incentives package. Iran's top nuclear negotiator has said the package's terms on uranium enrichment need to be clarified.

Hard-line clerics high in Iran's hierarchy have pressed Ahmadinejad's government to reject the deal outright, and Tehran may be taking a longer time than the West had hoped because of internal divisions.

Mottaki was headed to Berlin for talks Saturday with his counterpart, Frank-Walter Steinmeier. In an interview with the German weekly Der Spiegel this week, Steinmeier said a "solid answer from Tehran" was expected by the time G-8 foreign ministers meet in Moscow on June 29.

Ahmadinejad's timeframe would put the Iranian response well after that - and even after the G-8 summit in St. Petersburg, which begins July 15. Russia hopes G-8 leaders will adopt a common stance on the Iranian nuclear crisis at the summit.

Bush underlined that if Iran wants negotiations with the West it must suspend enrichment and called for Europe, Russia and China to maintain a "common front" toward Tehran.

"We'll come to the table when they verifiably suspend. Period," he said.