China and the Philippines have each unfurled their national flags on tiny sandbars in the South China Sea, staking competing sovereignty claims in strategic waters seen as a potential flashpoint for global conflict.

The standoff over Sandy Cay, which lies close to military outposts built by both Beijing and Manila, was the latest between the two nations.

Philippine Marines, National Police officers and Coast Guard members landed on three contested South China Sea features today to assert Manila’s maritime jurisdiction following a similar China Coast Guard action earlier this month.