China on Monday launched military drills around Taiwan, Beijing's defence ministry said, sending planes and ships to encircle the self-ruled island.

The exercises, dubbed Joint Sword-2024B, "test the joint operations capabilities of the theater command's troops", Beijing said.

They are taking place in "areas to the north, south and east of Taiwan Island" Captain Li Xi, spokesperson of the Chinese military's Eastern Theater Command, said.

The drills are "focusing on subjects of sea-air combat-readiness patrol, blockade on key ports and areas", Li said, as well as "assault on maritime and ground targets" and "joint seizure of comprehensive superiority".

Taiwan on alert as China aircraft carrier group detected

China has ramped up military activity around Taiwan in recent years, sending in warplanes and other military aircraft while its ships maintain a near-constant presence around the island's waters.

Beijing has not ruled out using force to bring the democratically-run island under its control.

China says 'no Taiwanese sovereignty'

The United States and Taiwan had urged China against taking action in response to a speech by Taiwanese President Lai Ching-te during the island's National Day celebrations last week.

Lai, who took office in May, has been more outspoken than his predecessor Tsai Ing-wen in defending Taiwan's sovereignty, angering the Chinese government, which calls him a "separatist".

In his speech on Thursday, Lai vowed to "resist annexation" of the island, and insisted Beijing and Taipei were "not subordinate to each other".

Taiwan President Lai vows to 'resist annexation' of island

Beijing on Monday said its drills served as a "stern warning to the separatist acts of 'Taiwan Independence' forces".

China says Taiwan president increasing 'hostility'

"It is a legitimate and necessary operation for safeguarding state sovereignty and national unity," Li said.

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© Agence France-Presse