BEIJING — The Chinese government scored a fresh diplomatic coup Monday over Taiwan and the United States after the Solomon Islands, a strategically significant archipelago in the Pacific Ocean, severed ties with Taipei in favor of Beijing.

The island nation’s defection whittled the number of countries that recognize Taiwan down to just 16 after Beijing flipped key allies, including the Dominican Republic and El Salvador, in recent years, over objections from Washington.

The development intensifies pressure on Taiwanese President Tsai Ing-wen, who has struggled to counter a mounting Chinese economic and diplomatic blockade designed to force Taiwan, a democracy of 23 million people, to the table for unification talks.

“The end of our relations with the Solomon Islands reflects China’s unceasing efforts to lure away our allies, damage the morale of the Taiwanese people, & force us to accept ‘one country, two systems,’ ” Tsai said on Twitter, referring to an offer by Chinese President Xi Jinping to bring Taiwan under Beijing’s control while allowing it to retain democratic freedoms.

“To this,” Tsai continued, “the people of Taiwan say: not a chance.”

China kick-started a campaign in 2016 to isolate Taiwan and throttle its economy after voters elected Tsai, who is bitterly opposed by the Communist government in Beijing because she leans toward declaring outright independence for Taiwan.

Since Tsai’s victory, China has pressured international corporations to recognize Taiwan as a part of China and successfully persuaded a half-dozen countries to swap allegiances, using generous aid packages to escalate pressure on Tsai’s Democratic Progressive Party. Tsai was beaten soundly in local elections last year and faces reelection in 2020. 

A task force formed by the Solomon Islands’ Parliament recommended this month that the government switch ties and set up a diplomatic mission in Beijing. Taiwan shot back with a warning last week that the country would fall into “economic slavery” if it aligned with China.

Solomon Islands Prime Minister Manasseh Sogavare, who has previously argued that siding with China would make far greater economic sense, endorsed the switch in a cabinet meeting Monday, Taiwan’s official Central News Agency reported.

The swap will enhance China’s growing presence in the string of lightly populated South Pacific islands where Taiwan and the United States — which fought key battles during World War II on Guadalcanal, the Solomons’ main island and site of its capital — once held sway. 

In recent years, the United States, Taiwan’s most important backer, has warned wavering countries such as El Salvador against abandoning Taiwan — to no avail. The Trump administration has stepped up its support for Taiwan and Tsai with arms sales as it seeks a tougher approach against China.

Taiwan has only small allies left in the Pacific, such as Palau and the Marshall Islands.

China’s Foreign Ministry did not immediately comment Monday, nor did the most authoritative state mouthpieces. The Communist Party-controlled Global Times said on social media that Taiwan was now all but isolated.

“After the Solomon Islands, they only have 16 ‘friends’ left, and most are micro-countries that people wouldn’t be able to locate,” the newspaper said.

China loosened its economic blockade during the administration of Taiwanese President Ma Ying-jeou, whose party, Kuomintang, favored closer ties to the mainland.

But Tsai, who does not recognize an informal 1992 agreement that asserts the existence of only “one China,” is anathema to Chinese leaders, who consider the agreement a nonnegotiable condition for cross-strait relations. 

Despite her diplomatic travails, Tsai appears to have gained some domestic support in recent months as anti-China protests have gripped Hong Kong, a territory to which Beijing has similarly promised political freedoms. Tsai handily beat back a primary challenge in June and has repeatedly warned voters that Taiwan could become the next Hong Kong if it aligns itself with China.

The “one country, two systems” framework could not work in Hong Kong, Taiwan or anywhere else, Tsai said in August, because “authoritarianism and democracy cannot coexist.”