China early Wednesday sent 21 military planes into Taiwan's air defence zone, Taipei claimed, as Beijing boasted that it had dispatched its elite J-20 stealth fighter jets toward the tiny island nation.

Beijing's fighter planes had earlier sent a warning as they buzzed the Taiwan Strait, the 100 mile-wide strip of water that separates the two nations, in the immediate aftermath of House of Representative speaker Nancy Pelosi's arrival in Taipei.

Chinese media confirmed its J-20 stealth jets had taken to the skies around the island, and two of Beijing's warships – a destroyer and a frigate – are in the seas to the east.

The Global Times reported: 'Additional important drills [were] announced for days to come.'

The firing of missiles into the Taiwan Strait would be the first such act since 1995, the last time there was deep concern about the possibility of all-out war.

Pictures posted on Chinese social network Weibo appeared to show tanks amassing on the coast of Fujian, the closest point on mainland China to the island.

In bizarre scenes, beachgoers stood watching as dozens of tanks rolled across the sand.

Columns of armoured vehicles were also seen moving through the nearby city of Xiamen, and a video posted on state media sites earlier this week showed off Chinese military hardware and urged troops to 'be ready to fight upon command, bury all incoming enemies'.

China considers Taiwan its territory and has indicated through repeated warnings that a visit from the US speaker of the House of Representatives would be a major affront.

China summons US ambassador over Pelosi's trip

China summoned the US ambassador in Beijing to rebuke him over House Speaker Nancy Pelosi's "egregious" trip to Taiwan, state media reported.

Vice Foreign Minister Xie Feng voiced "strong protests" over Pelosi's visit to the democratic self-governing island, which China considers part of its territory, during his talk with Ambassador Nicholas Burns.

"The move is extremely egregious in nature and the consequences are extremely serious," Xie was quoted as saying by China's state news agency Xinhua. "China will not sit idly by."

The trip by Pelosi, the highest-profile elected US official to visit Taiwan in 25 years, sent tensions soaring between the world's two largest economies, with Beijing regarding it as a major provocation.

Xie said the United States "shall pay the price for its own mistakes" and urged Washington to "immediately address its wrongdoings, take practical measures to undo the adverse effects caused by Pelosi's visit to Taiwan", Xinhua reported.

Pelosi landed in Taiwan late Tuesday, defying a string of angry warnings from Beijing.

While the Biden administration is understood to be opposed to Pelosi's Taiwan stop, White House National Security Council spokesman John Kirby said in Washington she was entitled to go where she pleased.

China's military said it was on "high alert" and would "launch a series of targeted military actions in response" to the visit. It announced plans for a series of military exercises in waters around the island to begin on Wednesday.

And Taiwan's defence ministry said more than 21 Chinese military aircraft had flown on Tuesday into the island's air defence identification zone -- an area wider than its territorial airspace that overlaps with part of China's own air defence zone.

"Taiwan is China's Taiwan, and Taiwan will eventually return to the embrace of the motherland. Chinese people are not afraid of ghosts, pressure and the evil," Xie told Burns, according to Xinhua.

There was no immediate comment from Washington.

China hits Taiwan with fresh trade curbs

China rolled out curbs Wednesday on the import of fruit and fish from Taiwan while halting shipments of sand to the island in the wake of a visit by US House Speaker Nancy Pelosi.

The trip by Pelosi, who is second in line to the presidency and the highest-profile elected US official to visit Taiwan in 25 years, has ignited a diplomatic firestorm.

She landed in Taiwan late Tuesday in the wake of increasingly stark warnings from China, which considers the island a part of its territory to one day be reclaimed, by force if necessary.

China's Customs Administration said Wednesday it would suspend some citrus fruits and fish imports from Taiwan over alleged "repeated" detection of excessive pesticide residue and positive coronavirus tests on packages.

In a separate notice, the Commerce Ministry added it would also "suspend the export of natural sand to Taiwan" from Wednesday, without providing details.

It is not the first time Beijing has taken aim at Taiwan's exports.

China banned pineapple imports from the island in March 2021, citing the discovery of pests, in a move that was widely seen as politically driven.

Beijing has ramped up pressure on Taiwan since President Tsai Ing-wen took office in 2016, as she views the island as a de facto sovereign nation and not part of "one China".

On top of the latest bans, Taipei's Council of Agriculture said on Tuesday that China had cited regulatory breaches in suspending the import of other Taiwanese goods, including fishery products, tea and honey.

Meanwhile, Chinese authorities also announced planned live-fire military drills encircling Taiwan, in a move Taipei's defence ministry said threatened the island's key ports and urban areas.

At some points, the zone of Chinese operations will come within 20 kilometres (12.4 miles) of Taiwan's shoreline, according to coordinates shared by the People's Liberation Army.

Taiwan's 23 million people have long lived with the possibility of an invasion, but that threat has intensified under current President Xi Jinping, China's most assertive leader in a generation.