China has held sea and air combat drills at disputed Scarborough Shoal, an uninhabited area of reefs and rocks it had seized from the Philippines in the South China Sea.

China declared its maritime baselines around Scarborough Shoal after the Philippines passed laws defining its maritime zones and sea lanes last week.

China on Sunday said it delimited the baselines of the territorial sea adjacent to Scarborough Shoal — which it calls Huangyan Dao — saying it’s a “natural step” to lawfully strengthen marine management. In response, Manila’s National Maritime ...