China warned on Friday of war over Taiwan and said it would ramp up countermeasures until "complete reunification" was achieved, as Chinese forces conducted military drills around the self-ruled island.

Warships and fighter jets encircled Taiwan on the second day of exercises that Beijing said were a test of its ability to seize the island, days after its new president was sworn in.

China's military kicked off the two-day war games on Thursday morning, surrounding democratic Taiwan with naval vessels and military aircraft as it vowed the blood of "independence forces" on the island would flow.

The exercises were launched three days after Lai Ching-te took office and made an inauguration speech that China denounced as a "confession of independence".

Beijing's defense ministry spokesman Wu Qian said on Friday that Lai "has seriously challenged the one-China principle... pushing our compatriots in Taiwan into a perilous situation of war and danger".

"Every time 'Taiwan independence' provokes us, we will push our countermeasures one step further, until the complete reunification of the motherland is achieved," he said.

The drills are part of an escalating campaign of intimidation by China in which it has carried out a series of large-scale military exercises around Taiwan in recent years.

They are testing the "capability of joint seizure of power, joint strikes and control of key territories", Li Xi, spokesman for the People's Liberation Army (PLA) Eastern Theater Command, said on Friday.

Fighter jets loaded with live ammunition scrambled towards targets and bombers formed formations to combine with warships to simulate "strikes against important targets", state broadcaster CCTV reported.

On Friday night, Taiwan's defense ministry said a total of 62 Chinese aircraft had been detected around the island since 7:14 am (2314 GMT Thursday), the highest number of aircraft seen this year in a 24-hour window.

The ministry also counted 27 naval and coast guard ships in the surrounding waters.

China, which split with Taiwan at the end of a civil war 75 years ago, regards the island as a renegade province which must eventually be reunified.

The dispute has long made the Taiwan Strait one of the world's most dangerous flashpoints, and this week's events have stoked fears that China may use military force to bring the island under mainland rule.

The United States, Taiwan's strongest ally and military backer, "strongly" urged China on Thursday to act with restraint. The United Nations called for all sides to avoid escalation.

'Common roots'

As the drills -- codenamed "Joint Sword-2024A" -- got under way, China said they would serve as "strong punishment for the separatist acts of 'Taiwan independence' forces".

Footage published by China's military showed soldiers streaming out of a building to battle stations and jets taking off to a rousing martial tune.

CCTV reported that Chinese sailors had called out to their Taiwanese counterparts at sea, warning them against "resisting reunification by force".

An animated graphic published by the Chinese military showed missiles raining down on key targets on the island, declaring it would "cut off the blood vessels for Taiwan independence!"

At a tourist park on Pingtan -- a Chinese island situated in the Taiwan Strait -- visitors clambered over the rocky landscape to gaze out at the misty horizon as pop music blared from a loudspeaker at nearby tea stalls.

Others posed for pictures in front of a sign proclaiming "the closest distance between the motherland and Taiwan island", 68 nautical miles (126 kilometres) away.

"We share common roots," Chen Yan, a 60-year-old woman from Wuhan, told AFP about Taiwan.

"So I think there will definitely be unification," she added.

'Heads broken'

China has repeatedly branded Lai a "dangerous separatist" who would bring "war and decline" to the island.

In a speech on Thursday, Lai said he would "stand on the front line" to defend Taiwan, without directly referring to the drills.

Beijing was incensed by his inauguration speech on Monday, in which he hailed a "glorious" era for Taiwan's democracy.

Chinese foreign ministry spokesman Wang Wenbin delivered a warning on Thursday that included language more commonly used by China's propaganda outlets.

"Taiwan independence forces will be left with their heads broken and blood flowing after colliding against the great... trend of China achieving complete unification," Wang told reporters.

Beijing's Xinhua news agency and ruling party organ the People's Daily ran editorials hailing the drills on Friday, while slamming Lai's "treacherous behavior" and promising a "severe blow".

The drills are taking place in the Taiwan Strait and to the north, south and east of the island, as well as areas around the Taipei-administered islands of Kinmen, Matsu, Wuqiu and Dongyin.

Beijing has said the drills will last until Friday but analysts say it could choose to extend the war games or launch missiles near Taiwan, as it did after a visit to the island by then-US House Speaker Nancy Pelosi in 2022. 

Taipei's defence ministry said the Chinese military had gotten within 24 nautical miles of Taiwan's main island.

Its coast guard reported on Friday that four Chinese vessels entered the "restricted waters" of two Taiwanese islands as two other vessels nearby provided support.