Throngs of supporters are celebrating outside the election headquarters of incumbent Taiwanese President Ma Ying-jeou, who secured another four-term term Saturday after beating opposition leader Tsai Ing-wen.

Cheers rose when Mr. Ma emerged to tell supporters, “We have won.”

With about 90 percent of the ballots counted, election officials said Mr. Ma had 51 percent of the vote, compared to about 46 percent for Ms.Tsai, who was attempting to become Taiwan's first female leader.

Ms. Tsai conceded defeat and apologized to supporters at her Democratic Progressive Party headquarters.

The election was being watched carefully in Beijing, where Chinese officials were hoping Mr. Ma would remain in office. Relations between China and Taiwan hit a low point during a previous period of rule by Ms. Tsai's DPP, which is more sympathetic than the Nationalists to calls for Taiwan's independence.

The outcome is also of concern to the United States, which is obliged by law to support Taiwan in the event of any hostilities with China. Beijing considers Taiwan a breakaway Chinese province and has threatened to use military force in the event of a declaration of independence.

Taiwan broke away from the mainland in 1949 at the end of the Chinese civil war in which Mao Zedong's communists defeated the nationalists under Chiang Kai-shek.

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