quarters of 1980, Zaire experienced slow progress to revive its weakened economy in order to keep up its rescheduled payment on the country's debt of $4.4 billion. During the 1980s, Zaire remained a one-party state. Although Mobutu successfully maintained control during this period, opposition parties, most notably the Union for Democracy and Social Progress (Union pour la Démocratie et le Progrès Social—UDPS), were active. Mobutu's attempts to quell these groups drew significant international criticism. As the Cold War came to a close, internal and external pressures on Mobutu increased. In late 1989 and early 1990, Mobutu was weakened by a series of domestic protests, by heightened international criticism of his regime's human rights practices, by a faltering economy, and by government corruption, most notably his massive embezzlement of government funds for personal use. In June 1989, Mobutu visited Washington, D.C., where he was the first African head of state to be invited for a state meeting with newly elected U.S. President George H. W. Bush. In May 1990, Mobutu agreed to the principle of a multi-party system with elections and a constitution. As details of a reform package were delayed, soldiers began looting Kinshasa in September 1991 to protest their unpaid wages. Two thousand French and Belgian troops, some of whom were flown in on U.S. Air Force planes, arrived to evacuate the 20,000 endangered foreign nationals in Kinshasa. In 1992, after previous similar attempts, the long-promised Sovereign National Conference was staged, encompassing over 2,000 representatives from various political parties. The conference gave itself a legislative mandate and elected Archbishop Laurent Monsengwo Pasinya as its chairman, along with Étienne Tshisekedi wa Mulumba, leader of the UDPS, as prime minister. By the end of the year Mobutu had created a rival government with its own prime minister. The ensuing stalemate produced a compromise merger of the two governments into the High Council of Republic–Parliament of Transition (HCR–PT) in 1994, with Mobutu as head of state and Kengo wa Dondo as prime minister. Although presidential and legislative elections were scheduled repeatedly over the next 2 years, they never took place. First Congo War and demise By 1996, tensions from the neighbouring Rwandan Civil War and genocide had spilled over to Zaire (see History of Rwanda). Rwandan Hutu militia forces (Interahamwe), who had fled Rwanda following the ascension of an RPF-led government, had been using Hutu refugee camps in eastern Zaire as bases