New Taiwan President Lai Ching-te on Monday vowed to defend the island's democracy, as he called on China to end its military intimidation of the self-ruled island.

Beijing, which has in the past branded Lai a "dangerous separatist", responded hours later saying that his speech had sent a "dangerous signal".

In his inauguration speech, Lai directly addressed the threat of war following years of growing pressure from China to bring democratic Taiwan under mainland rule.

Lai said a "glorious era of Taiwan's democracy has arrived" and thanked citizens for "refusing to be swayed by external forces, for resolutely defending democracy".

"In face of the many threats and attempts of infiltration from China, we must demonstrate our resolution to defend our nation and we must also raise our defence awareness and strengthen our legal framework for national security," said Lai, 64.

Having previously described himself as a "pragmatic worker for Taiwan independence", Lai has moderated his rhetoric on the issue in recent years.

On Monday, he said his government would "neither yield nor provoke, and maintain the status quo" -- a balance that preserves Taiwan's sovereignty while not declaring formal independence.

"I also want to call on China to cease their political and military intimidation against Taiwan," Lai said.

He reiterated that the Republic of China -- the island's official name -- and the People's Republic of China "are not subordinate to each other".

He urged Beijing to "share with Taiwan the global responsibility of maintaining peace and stability in the Taiwan Strait... and ensure the world is free from the fear of war".

Lai has made repeated overtures to resume high-level communications with China, which Beijing severed in 2016 when his predecessor Tsai Ing-wen took power.

On Monday Lai said he hoped China would "choose dialogue over confrontation".

Hours after his speech, Beijing's foreign minister Wang Yi said "China's unification is irreversible".

"The secessionist behaviour of 'Taiwan independence' (forces) constitutes the most serious challenge to the international order, the most dangerous change to the status quo in the Taiwan Strait," Wang said, without naming Lai.

Beijing's Taiwan Affairs Office -- which manages relations with the island -- also slammed Lai's speech as sending a "dangerous signal", state news agency Xinhua reported.

 US support 

 Taiwan has been self-governed since 1949 when nationalists fled to the island following their defeat by communist forces in a civil war on mainland China.

For more than 70 years, China has considered Taiwan as part of its territory and has long threatened to use force to bring the island under its control.

The United States switched diplomatic recognition from Taiwan to China in 1979 but remains the island's most important partner and biggest arms supplier.

Lai is expected to further boost defence ties with Washington during his four-year term.

US Secretary of State Antony Blinken on Monday congratulated Lai, saying he was looking forward to Washington and Taipei deepening ties and maintaining "peace and stability across the Taiwan Strait".

As Lai took office, Chinese state media reported Beijing imposed sanctions on three US defence companies over their sales of weapons to Taipei.

Chinese warplanes and naval vessels maintain a near-daily presence around the island, but in recent days there has not been a significant uptick in the numbers.

Around 7:00 pm local time (1100 GMT), Taipei's ministry of defence announced it had detected eight Chinese navy vessels around the island in the past 13 hours.

Lai and Vice President Hsiao Bi-khim -- Taiwan's former top envoy to Washington -- are both part of the Democratic Progressive Party (DPP), which has championed Taiwan's sovereignty.

China has dubbed them an "independence duo".

 'Expand investment' 

 With only 12 formal allies, Taipei lacks diplomatic recognition on the world stage.

Eight heads of state who recognise Taiwan attended Lai's inauguration ceremony.

More than 40 other countries, including the United States, Japan and Canada, also sent delegations.

Taiwan has its own government, military and currency, and the majority of the 23 million population see themselves as having a distinct Taiwanese identity, separate from the Chinese.

"I think it is better not to be too close to China or too far away from China -- it is better to maintain a neutral feeling," said Shen Yujen, 24, who is part-way through his four-month military service.

Domestically, Lai faces another challenge after his DPP lost its majority in the legislature in the January elections, meaning it will be hard for him to push through his policies.

Many Taiwanese are less worried about the threat of conflict than they are about soaring housing prices, rising costs of living, and stagnated wages.

Lai on Monday vowed to "expand investment in society" and ensure the island becomes a "force for global prosperity".