TOKYO — Taiwan's Vice President Lai Ching-te, who heads the ruling Democratic Progressive Party, declared victory in Saturday's presidential election and vowed to protect the self-ruled island from the growing threat posed by mainland China.

In the race closely watched by the world amid China's unrelenting pressure on Taiwan, Lai's victory means the DPP has secured a third consecutive four-year term, an unprecedented run of success in the period since the direct leadership poll was introduced in 1996.

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The election commission said voter turnout was 71.9 percent. Lai secured 40.1 percent of votes and Hou Yu-ih of the main opposition Nationalist Party, or Kuomintang, won 33.5 percent, according to final results released by the commission.

Ko Wen-je of the Taiwan People's Party, the second-largest opposition force, got 26.5 percent.

"As president, I have an important responsibility to maintain peace and stability in the Taiwan Strait," Lai, 64, told his supporters in Taipei. "We are also determined to safeguard Taiwan from continuing threats and intimidation from China."

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Communist-led China, which aims to bring the island into its fold, by force if necessary, has slammed Lai as an independence advocate and a "troublemaker." The two sides have been governed separately since they split in 1949 due to a civil war.

China said late Saturday that Lai's victory will not stop "the inevitable trend" of the unification between the mainland and Taiwan.

"Our stance on resolving the Taiwan question and realizing national reunification remains consistent, and our determination is as firm as rock," Chen Binhua, a spokesman for the State Council Taiwan Affairs Office, said in a statement carried by the official Xinhua News Agency.

Lai also said Taiwan "will stand on the side of democracy," noting that the Taiwanese people have successfully resisted election interference by external forces, namely China. "We trust that only the people of Taiwan have the right to choose their own president," he said.

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The vice president, who will be inaugurated on May 20, pledged to inherit President Tsai Ing-wen's foreign affairs and defense policies and called on Beijing, which has shunned talks with the DPP government since Tsai took office in 2016, to work toward peace that will benefit both sides of the Taiwan Strait.

"Under the principles of dignity and parity, we will use exchanges to replace obstructionism, dialogue to replace confrontation, and confidently pursue exchanges and cooperation with China," Lai said.

Hou, 66, apologized to his supporters at a rally in New Taipei for failing to bring about a change of government, saying, "I let everybody down...I'm sorry to everyone."

Ko, a 64-year-old former Taipei mayor, also conceded defeat and thanked his supporters for showing to the world that Taiwan has not only the two major parties of the DPP and KMT but also his own party.

"Most importantly, we have demonstrated to the world that democracy has always been the most important asset of Taiwan," Ko said in New Taipei.

All three candidates had called for maintaining the status quo in the Taiwan Strait if elected, seeking neither the island's independence nor its unification with mainland China.

Hou and Ko both sought dialogue with Beijing during the campaign.

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Japan congratulated Lai on his victory, with Foreign Minister Yoko Kamikawa saying in a statement that Tokyo will "work toward further deepening cooperation and exchanges" with Taipei.

"We expect that the issues surrounding Taiwan will be resolved peacefully by dialogue, thereby contributing to the peace and stability in the region," she said.

US Secretary of State Antony Blinken also congratulated Lai and expressed Washington's commitment to maintaining cross-strait peace and stability and the peaceful resolution of differences, free from coercion and pressure.

"The partnership between the American people and the people on Taiwan, rooted in democratic values, continues to broaden and deepen across economic, cultural, and people-to-people ties," he said.

In the legislative election, where 113 seats were up for grabs, the DPP failed to hold on to a majority, with the number of its seats declining from 62 to 51.

Lai said the result meant "we did not work hard enough and there are areas where we must humbly review and look back on."

The KMT secured the most seats at 52, 15 more than before, but still falling short of a majority, according to the official election results. The TPP won eight seats, up by three, and is forecast to hold the balance of power.