BEIJING, Nov 21 (Reuters) - China downgraded its diplomatic ties with Lithuania expressing strong dissatisfaction with Vilnius for allowing Taiwan to set up a de facto embassy in the Baltic state, China"s foreign ministry said in a statement on Sunday. The statement, posted on the foreign ministry"s official website, read in part: "Lithuania ignored the solemn stance of the Chinese government, disregarded the overall situation of bilateral relations, and ignored the basic norms of international relations" in allowing Taiwan to set up a representative office in Lithuania. China urges Lithuania to "correct the mistake" as soon as possible, the statement said. China had demanded in August that the Baltic state withdraw its ambassador to Beijing and said it would recall China"s envoy in Vilnius after Taiwan announced its office in the city would be called the Taiwanese Representative Office in Lithuania. Other Taiwan offices in Europe and the United States use the name of the city Taipei, avoiding a reference to the island itself, which China claims as its own territory. China has stepped up efforts to get other countries to limit their interactions with Taiwan, or cut them off altogether. Only 15 countries have formal diplomatic ties with Taiwan.