President Bush says Iran's initial response to an international plan designed to resolve the impasse over its nuclear program appears positive. The package of incentives and threats was formally presented to the Tehran government Tuesday by a senior European Union official.

Iran reacted cautiously to the offer. The country's chief nuclear negotiator, Ali Larijani, called it positive, but also said it contains some ambiguities.

President Bush, second right, stands with Homeland Security Secretary Michael Chertoff after his speech about border security and immigration reform at the Federal Law Enforcement Training Center in Artesia, New Mexico

President Bush was asked about the comments a few hours later while touring America's southern border. Speaking to reporters in Laredo, Texas, the president appeared hopeful. "I think that is positive. I want to solve this issue with Iran diplomatically," he said.

Mr. Bush noted the package of incentives and threats was drafted by the three countries that have been negotiating with Iran, Britain, France and Germany, with input from the United States, China and Russia. He said Iran now knows all these countries want the problem resolved. "And so we will see if the Iranians take our offer seriously. The choice is theirs to make," he said.

The president noted that the United States has offered to join multi-lateral negotiations with Iran if Tehran suspends uranium enrichment and reprocessing activities in a verifiable way.

Iran says it needs to produce fuel for its nuclear power plants. But the United States and its allies are concerned Tehran's civilian nuclear program may be a cover for the development of nuclear arms.

Javier Solana (l) meeting in Tehran with Iran's Foreign Minister Manouchehr Mottaki

Months of negotiations between the Europeans and Iran have done little if anything to resolve the impasse. And the package presented to Iran by European Union foreign policy chief Javier Solana is part of a stepped-up effort to find a peaceful solution.

Details have not been made public, but the package is believed to include support for civilian power plants, and perhaps access to American and European airline parts for the aging Iranian aviation fleet. It also includes the threat of possible U.N. action if it is rejected by Tehran.

During a briefing at the State Department, spokesman Sean McCormack said the Iranians told Solana they want some time to study the offer. McCormack indicated Washington does not expect an immediate answer, but added Tehran has weeks, not months, in which to make a decision.