A large number of sensitive nuclear components sold to Iran and Libya for building uranium enrichment plants were made at workshops in Europe and Southeast Asia, says a Washington-based nuclear monitoring agency. In a recent report on the nuclear black market, the Institute for Science and International Security confirms Pakistan's claim that the network might have been headed by a Pakistani, Dr A.Q. Khan, but it was a gang of international proliferators and smugglers that had bases and workshops at many places across the globe. The ISIS report says that the centrifuges the network sold to Iran and Libya are formally called Pakistan 1 and Pakistan 2 but are better known by their acronyms, P1 and P2. They are used for uranium enrichment and were deployed in large numbers by Pakistan's gas centrifuge programme. The P1 centrifuge uses an aluminium rotor, and the P2 centrifuge uses a steel rotor. The components for roughly 500 P1 centrifuges that went to Iran in the mid-90s were from centrifuges that Pakistan had retired from its main centrifuge programme. Members of the network were able to remove them in secret and sell them to Iran. Libya received 20 of its P1s in that manner. Libya also bought about 200 P1 centrifuges from the wider network. At least some, if not all, of the components of the additional 200 P1s were made outside Pakistan at workshops under contract with companies in the network. Aluminium rotors, for example, were made in Malaysia.