China launched its largest-ever air and sea exercises around Taiwan last week in a furious response to a visit by US House Speaker Nancy Pelosi, the highest-ranking American official to visit the self-ruled island in decades.

Taiwan lives under the constant threat of invasion by China, which views its neighbour as part of Chinese territory to be seized one day, by force if necessary.

"China has used the drills in its military playbook to prepare for the invasion of Taiwan," foreign minister Joseph Wu told a press conference in Taipei on Tuesday, accusing Beijing of using Pelosi's visit as a pretext for military action.

"China's real intention is to alter the status quo in the Taiwan Strait and entire region."

The Chinese military said its Taiwan drills continued Tuesday and involved air and sea units.

The Eastern Theater command of the People's Liberation Army said in a statement that it was conducting training exercises around the island, "focusing on joint blockade and joint support operations".

Taipei's drill in the southern county of Pingtung included the firing of target flares and artillery, lasting just under an hour, said Lou Woei-jye, spokesman for Taiwan's Eighth Army Corps.

Soldiers fired from howitzers tucked into the coast, hidden from view of the road that leads to popular beach destination Kenting.

The drills, which will also take place Thursday, included the deployment of hundreds of troops and about 40 howitzers, the army said.

Tuesday's exercise attracted a crowd of onlookers.

"We need to have some countermeasures against mainland China's blockade," said one of the spectators, who only gave his surname Chen.

"Conducting military drills will also let them know Taiwan is prepared. I hope both sides can have some restraint."

On Monday, spokesman Lou told AFP the drills were previously scheduled and were not in response to China's exercises.

The island routinely stages military drills simulating defence against a Chinese invasion.

But the latest drill prompted an ominous warning from Beijing, which regularly unleashes fiery rhetoric against Taiwan's independence hopes.

"Any conspiracy to go against the trend of history and resist reunification through arms... will end in failure like a mantis trying to stop a chariot," foreign ministry spokesman Wang Wenbin told a regular briefing Tuesday.

- 'Not worried' -

The anti-landing exercise took place after China extended its own joint sea and air drills around Taiwan on Monday, but Washington said it did not expect an escalation from Beijing.

"I'm not worried, but I'm concerned they're moving as much as they are. But I don't think they're going to do anything more than they are," Biden told reporters at Dover Air Force Base.

Taiwan's Wu on Tuesday condemned Beijing for pressing on with military exercises around the island, accusing them of trying to control the Taiwan Strait and waters in the wider Asia-Pacific region.

"It is conducting large-scale military exercises and missile launches, as well as cyber-attacks, a disinformation campaign and economic coercion in order to weaken public morale in Taiwan," he said.

Wu went on to thank Western allies, including the US, for standing up to China.

"It also sends a clear message to the world that democracy will not bow to the intimidation of authoritarianism," he said.

Taiwan has insisted that no Chinese warplanes or ships entered its territorial waters -- within 12 nautical miles of land -- during Beijing's drills.

But its defence ministry said Tuesday the extension of the drills showed China's "threat of force has not diminished" around the island and all of its units would "maintain combat readiness".

The Chinese military released a video last week of an air force pilot filming the island's coastline from his cockpit, showing how close it came to Taiwan's shores.

Its ships and planes have also regularly crossed the median line -- an unofficial demarcation between China and Taiwan that the former does not recognise -- since drills began last week.

On Tuesday, the Chinese military released more details about the anti-submarine drills it had conducted a day earlier around the island.

The Eastern Theater command said the exercises were aimed at enhancing the ability of air and sea units to work together while hunting submarines.

The scale and intensity of China's drills -- as well as its withdrawal from key talks on climate and defence -- have triggered outrage in the United States and other democracies.

But foreign ministry spokesman Wang on Monday defended Beijing's behaviour as "firm, forceful and appropriate" to American provocation.

"We urge the US to do some earnest reflection, and immediately correct its mistakes," he told a regular briefing.