Mountains cover more than 90 percent of this Central Asian republic, whose river valleys are home to a majority of the people. About two-thirds of the people are ethnic Tajiks, but about a quarter are Uzbeks. Shortly after independence in 1991, Tajikistan endured a five-year civil war between the Moscow-backed government and the Islamist-led opposition. A peace agreement was signed in 1997, but the political turmoil has depressed the economy. Tajikistan relies heavily on Russian assistance, and there are some 23,000 Russian troops guarding Tajikistan's borders—against weapons, drugs, and Islamic extremists.