Beijing will not tolerate "separatist activities" in Taiwan after the re-election of Lai Ching-te on Saturday, an official statement said Saturday.
"We will adhere to the 1992 Consensus that embodies the one-China principle and firmly oppose the separatist activities aimed at 'Taiwan independence' as well as foreign interference," Beijing's Taiwan Affairs Office spokesperson Chen Binhua said in a statement carried by state news agency Xinhua.
China's Taiwan Affairs Office said that the election would not change the basic landscape of cross-strait relations.
In a statement carried on China's state Xinhua news agency, Chen Binhua, a spokesperson for the State Council Taiwan Affairs Office, said the results showed the Democratic Progressive Party cannot represent mainstream public opinion on the island.
Taiwan's president-elect Lai Ching-te vowed Saturday to defend the self-ruled island from "intimidation" from China after voters defied warnings from Beijing and swept him to election victory.
Lai – branded by Beijing as a threat to peace in the flashpoint region – secured an unprecedented third consecutive term for the Democratic Progressive Party (DPP) after a raucous campaign in which he pitched himself as the defender of Taiwan's democratic way of life.
China claims Taiwan, separated from the mainland by a 180-kilometer (110-mile) strait, as its own and refuses to rule out using force to bring about "unification," even if conflict does not appear imminent.
Beijing, which before the poll called Lai a "severe danger" and urged voters to shun him, said Saturday the result would not stop "the inevitable trend of China's reunification".
In his victory speech Lai said he would maintain peace and stability in the Taiwan Strait, but pledged to defend the island from Chinese belligerence.
"We are determined to safeguard Taiwan from continuing threats and intimidation from China," he told supporters.
With votes from virtually all polling stations counted, the Central Election Commission said Lai won 40.1% of votes, ahead of Hou Yu-ih of the opposition Kuomintang (KMT) at 33.5%.
The election was watched closely by both Beijing and Washington, Taiwan's main military partner, as the two superpowers tussle for influence in the strategically vital region.
Lai thanked the Taiwanese people for "writing a new chapter in our democracy" by defying one-party China's threats and warnings.
"We are telling the international community that between democracy and authoritarianism, we will stand on the side of democracy," he said, adding that he will also try to pursue exchanges with China.
Leading up to Saturday's poll, authorities have repeatedly warned of interference from China, pointing to paid trips to the mainland for voters and flagging instances of disinformation that painted Lai in a negative light.
After his win, Lai said the island had "successfully resisted efforts from external forces to influence this election".
The victory extends DPP's rule after eight years under outgoing President Tsai Ing-wen, who had served the maximum two four-year terms.
Supporters dressed in the party's green colors celebrated at DPP headquarters.
"We are very, super, world-class happy," said first-time voter Grace, 21, a student who gave only one name.
"I am confident the new leaders will stick to Tsai's road and I hope they can safeguard Taiwan's democracy."
Conceding defeat, KMT's Hou, who had argued for warmer ties with China and accused the DPP of antagonizing Beijing with its stance that Taiwan is "already independent," urged the country to unite.
"When the people have made their decision, we face them and we listen to the voices of the people," he told supporters.
Ko Wen-je – who took 26.4% of the vote with an anti-establishment offer of a "third way" out of the two-party deadlock – said the results put his Taiwan People's Party (TPP) on the map as a "key opposition force."
"Ko Wen-je will not give up on building Taiwan into a sustainable country and I would like to appeal to you not to give up as well," he told supporters.
During the campaign, the KMT and TPP tried to strike a deal to join forces against the DPP, but the partnership collapsed in public acrimony over who would lead the presidential ticket.
Despite the presidential win, Lai faces a headache already -- in legislative elections held alongside the presidential ballot, the DPP lost its majority in the 113-seat parliament.
KMT took 52 seats, with DPP on 51, TPP eight and two independents.
Located on a key maritime gateway linking the South China Sea to the Pacific Ocean, Taiwan is home to a powerhouse semiconductor industry producing precious microchips – the lifeblood of the global economy powering everything from smartphones and cars to missiles.
The European Union's foreign policy chief congratulated Taiwan on the election in a statement that did not mention Lai's victory.
China has stepped up military pressure on Taiwan in recent years, periodically stoking worries about a potential invasion.
Chinese warplanes and naval ships probe Taiwan's defenses almost daily and Beijing has also staged massive war games in recent years – simulating a blockade of the island and sending missiles into its surrounding waters.
The Chinese military said the night before the polls that it would "take all necessary measures to firmly crush 'Taiwan independence' attempts of all forms."