Xi's comments, made on a naval inspection trip on Tuesday, come amid heightened tension in the region after the show of force by Beijing, which sees self-ruled Taiwan as its territory.

China on Monday concluded three days of military drills launched in response to a visit last week by Taiwan's President Tsai Ing-wen to the United States, where she met a bipartisan group of lawmakers.

Xi on Tuesday told the People's Liberation Army's Southern Theatre Command Navy that the military must "resolutely defend China's territorial sovereignty and maritime interests, and strive to protect overall peripheral stability", state broadcaster CCTV reported.

Beijing is also enraged by a plan for US forces to use a growing number of bases in the Philippines, including one near Taiwan.

The United States and the Philippines are holding their largest-ever joint military drills this week, with US Secretary of State Antony Blinken committing to "standing with the Philippines against any intimidation or coercion, including in the South China Sea".

Xi added Tuesday that China must be "innovative in its concepts and methods of combat".

- Disputed waters -

China and Taiwan split following a civil war in 1949.

Beijing views the democratic island as part of its territory and has vowed to take it one day, stepping up its rhetoric and military activity around the island in recent years.

Washington has been deliberately ambiguous on whether it would defend Taiwan militarily.

But for decades it has sold weapons to Taipei to help ensure its self-defence, and offered political support.

At the same time, China claims sovereignty over almost the entire South China Sea -- a strategic waterway through which trillions of dollars in trade pass annually -- despite an international court ruling that the assertion has no legal basis.

The Philippines, Vietnam, Malaysia and Brunei all have overlapping claims in the sea, while the United States sends naval vessels through it to assert freedom of navigation in international waters.