Pakistan is one of nine states to possess nuclear weapons, and the only Muslim majority country to do so. Pakistan began development of nuclear weapons in January 1972 under Prime Minister Zulfikar Ali Bhutto, who delegated the program to the Chairman of PAEC Munir Ahmad Khan with a commitment to have the bomb ready by the end of 1976. Since PAEC, consisting of over twenty laboratories and projects under nuclear engineer, Munir Ahmad Khan was falling behind schedule and having considerable difficulty producing fissile material, Abdul Qadeer Khan was brought from Europe by Zulfikar Ali Bhutto at the end of 1974. As pointed out by Houston Wood, Professor of Mechanical & Aerospace Engineering, University of Virginia, Charlottesville, USA in his article on gas centrifuges, "The most difficult step in building a nuclear weapon is the production of fissile material", so this work in producing fissile material as head of the Kahuta Project was pivotal to Pakistan developing the capability to detonate a nuclear bomb by the end of 1984.