unofficial diplomatic relations with Taiwan. This number includes 59 sovereign states, 3 dependent or quasi-dependent territories, and the European Union. Unofficial diplomatic relations typically involve an "Economic, Trade and Cultural Office" in Taiwan for the partner country, as well as a corresponding "Taipei/Taiwan/ROC Representative Office" representing Taiwan within the partner country. These unofficial offices generally function as embassies despite not being officially named as such. For example, the American Institute in Taiwan functions as the United States' de facto embassy, with the chairman and staff acting as unofficial government consulate officers who nevertheless perform duties that official embassies would undertake. Various countries host Taiwanese representative offices within themselves but don't have representative offices in Taiwan. One country, Luxembourg, has a representative office in Taiwan but does not host a Taiwanese representative office within itself; Taiwan's interests in Luxembourg are served by the Taipei Representative Office in the EU and Belgium. Taiwan also regards the European Union, with which it also has unofficial relations via the Taipei Representative Office in the EU and Belgium, as a state entity in the context of international relations; the EU is a supranational union with a high level of integration between its member states, though each member state retains its national sovereignty. Taiwan has unofficial diplomatic relations with Hong Kong and Macau, both of which are Special Administrative Regions of the PRC, though Taiwan does not have similar such relations with mainland China (the PRC). Technically, Hong Kong and Macau are integral territories of the PRC, governed under the "One Country, Two Systems" framework. This means that Taiwan effectively has unofficial relations with parts of the PRC but not with the national government of the PRC itself. Taiwan maintains hostile relations with the PRC through the Mainland Affairs Council, whose counterpart is the Taiwan Affairs Office; neither office is considered to be an embassy by either Taiwan or the PRC, and both offices are operated within the home country rather than within the host country. Taiwan has strong unofficial relations with Somaliland, which is a self-declared state in the Horn of Africa that is claimed as the territory of neighbouring Somalia, in a state of affairs that displays strong parallels to Taiwan's own sovereignty dispute with China. Taiwan maintains a "Taiwan Economic and Cultural Office" in Guam, which is an external territory of the United States located in Oceania. In 2021, Lithuania announced that it