Iran hasn't provided a "final answer" to a "unique" international nuclear fuel offer, Mohamed ElBaradei, the outgoing head of the U.N. nuclear watchdog, said Friday.

Iran hasn't provided a "final answer" to a "unique" international nuclear fuel offer, Mohamed ElBaradei, the outgoing head of the U.N. nuclear watchdog, said Friday.

"I do not consider that I have received a final answer," ElBaradei, chief of the International Atomic Energy Agency, said in Berlin. "But I also very much hope that I will get an answer pretty much soon."

"We have not received any written response from Iran. What I got of course is an oral response, which basically said 'we need to keep all the material in Iran until we get the fuel.' That to me is a case of extreme mistrust.

"I believe that frankly the ball is very much in the Iranian court. I hope that they will not miss this unique and fleeting opportunity."

In an attempt to draw Iran into talks and guarantee that its nuclear ambitions are peaceful, six world powers have offered to reprocess some of its low-enriched uranium abroad.

But Iran Wednesday appeared to reject the proposal out of hand, prompting U.S. President Barack Obama to warn of "consequences" in the form of toughened sanctions.

Representatives from the six powers--the U.S., China, Russia, the U.K., France and Germany--were meeting in Brussels Friday to discuss the next steps in what ElBaradei called "an environment of desperation."