The State Department denounced Iran's actions. ''You've given the world cause for concern," spokesman Adam Ereli said. ''The international community doesn't like what it sees, and it doesn't like the kind of behavior that you've been exhibiting over the last several years."
He urged Iran to be more forthcoming with the International Atomic Energy Agency at its 35-nation meeting next week. He said that if Tehran chooses to remain silent, it increases chances of becoming more isolated.
''If a nation thinks that it's in their interest to tell the rest of the world to go take a leap, they can do that," Ereli said. ''But that would certainly be unusual and ill-advised."
Undersecretary of State Nicholas R. Burns flew to London Thursday for talks with European and Russian ministers.
The European Union, with US support, has been calling on Iran to reimpose a freeze on conversion since August. But the nation's top nuclear negotiator, Ali Larijani, told state television the country had started converting the second batch of uranium.
''This job is done and the plant is continuing its activity," Larijani said in an interview broadcast yesterday.
One idea under consideration is to permit Iran to convert uranium but to move the enrichment process to Russia, thereby hopefully denying Iran the capacity to produce weapons grade uranium for nuclear weapons. President Bush confirmed reports of US approval of the compromise in a meeting yesterday in South Korea with Russian President Vladimir Putin.
The IAEA said Iran received the detailed designs from the network run by Abdul Qadeer Khan, the father of Pakistan's nuclear program. His network supplied Libya with information for its now-dismantled nuclear weapons program that included an engineer's drawing of an atomic bomb.
The document given to Iran in 1987 showed how to cast ''enriched, natural, and depleted uranium metal into hemispherical forms," said a confidential IAEA report. IAEA officials refused to comment on the implications of the finding.
But diplomats close to the agency said it appeared to be a design for the core of a nuclear warhead.
