For a long time, China's main security priority in Central Asia was mitigating the threat of Uighur separatist groups operating in the region. The country has been carrying out an aggressive and decadeslong campaign to assimilate its Uighur population, provoking a low-level insurgency against Beijing's rule from among the minority group. In response, Beijing has cracked down further, forcing many Uighur groups — violent and nonviolent — to flee the country. Many sought refuge in Central Asia, which already had small indigenous Uighur communities. Consequently, most of China's joint military exercises with Central Asian armed forces have involved fighting separatists and terrorists. The Shanghai Cooperation Organization (SCO) — a regional group that also includes Russia, Kazakhstan, Uzbekistan, Kyrgyzstan and Tajikistan — focuses its security efforts in Central Asia on combating terrorism, extremism and separatism.