DULAN, Taiwan — The Solomon Islands has reportedly decided to break diplomatic relations with the government of Taiwan in order to establish official ties with China, dealing a blow to both Taipei’s global standing and Washington’s regional diplomacy in the Pacific.

Joseph Wu, the Taiwanese foreign minister, said at a news conference on Monday that Taiwan had learned that the Solomons, an archipelago east of Australia, had chosen to end 36 years of recognition of Taiwan’s government, leaving only 16 countries that maintain official relations with Taipei. These countries are the most likely to speak up for Taiwan in international bodies such as the United Nations General Assembly, where Taipei is not a member.

For the United States, the Solomons’ decision is a setback in its effort to prevent China from continuing to make diplomatic inroads among island nations in the Pacific, a region of increasing geostrategic competition between Washington and Beijing. Five of the nations that still have diplomatic ties with Taiwan are in the region.

China’s Communist Party claims self-governing Taiwan as its territory, but has never ruled it. Beijing has intensified its efforts to peel off Taiwan’s remaining official allies, and some have found China’s economic might too much to resist.