The competing claims are reigniting tensions in the South China Sea and coincide with joint military drills between the U.S. and the Philippines.

China has claimed sovereignty over an uninhabited reef in the South China Sea, according to state media, setting the stage for an escalation of tensions with the Philippines over the disputed area.

Both countries have planted flags on a collection of sand bars, extending the clash over the area between Beijing and Manila, a U.S. ally.