"The IAEA wants Iran to detail research into P-2 centrifuges, able to enrich uranium fuel to bomb-grade level faster than the P-1 centrifuges it now operates, and credibly clarify its possession of documents showing how to make an atom bomb core.

Another key issue, the IAEA says, is Tehran's failure to explain intelligence reports of links between work on processing of uranium ore, explosives tests and a missile warhead design.

ElBaradei has said that, overall, Iran has not proven it does not harbour a military nuclear programme at undeclared locations, and Tehran's halt to short-notice IAEA inspections in February has magnified such concerns.

The Islamic Republic threatened on Tuesday to freeze ties with the IAEA -- which Vienna diplomats said would amount to quitting the nuclear Non-Proliferation Treaty -- and accelerate its atomic programme if it were hit by international sanctions.

The crisis has escalated with Iran's public spurning of the Security Council's March 29 call -- Tehran has announced it can purify uranium for use in fuelling power stations and that it has an active P-2 centrifuge research programme."

http://www.cnn.com/2006/WORLD/meast/04/26/iran.nuclear.reut/index.html