In 1980, Libya began to build its nuclear infrastructure from various nuclear black market sources. The centrifuges materials and expertise were provided by Swiss national, Friedrich Tinner. Tinner's work on centrifuges took place at the TNRF aimed at producing gas centrifuges for uranium enrichment. By the late 1980s, financial constraints and economic sanctions were imposed by the United States in the 1980s, further hampering the nuclear program. Work was completed by Tinner in 1992, but Libya remained unable to produce an operating centrifuge. After the end of Cold War, Gaddafi bluntly persuaded the U.S. President Bill Clinton to uplift the sanctions by allowing the disarmament of its nuclear program.