Bush Warns Iran After Uranium Processing Reports.

SANTIAGO, Chile (Reuters) - President Bush on Saturday warned Iran of growing international concern over reports that Tehran is preparing large amounts of uranium for an enrichment process that can be used to make nuclear weapons.

“This is a very serious matter. The world knows it’s a serious matter and we’re working together to solve this matter,” Bush told reporters during a meeting with Japanese Prime Minister Junichiro Koizumi in Santiago.

The two leaders were in Chile for a summit hosted by the Asia Pacific Economic Cooperation forum.

Bush was referring to reports from diplomats that Iran was aggressively producing uranium hexafluoride, or UF6, days before a Nov. 22 deadline by which Tehran promised the European Union that it would freeze enrichment and all related activities.

UF6 is the form of uranium that is fed into gas centrifuges, which purify uranium for use as fuel in nuclear power plants or weapons.

Iran had promised France, Britain and Germany to freeze its enrichment program in a bid to ease concerns that its nuclear plans are aimed at producing atomic weapons and to escape a referral to the U.N. Security Council when the International Atomic Energy Agency, or IAEA, meets on Nov. 25.

“It’s very important for the Iranian government to hear that we are concerned about their desires,” Bush said.

“We’re concerned about reports that show that prior to a certain international meeting, they’re willing to speed up processing of materials that could lead to a nuclear weapon.”