The United States, Japan, Australia and the Philippines have begun joint naval drills in the South China Sea, a move aimed at improving coordination among the four militaries as tensions remain high in the contested waterway.

According to Reuters, the exercise started on Monday and is meant to strengthen interoperability and support freedom of navigation in one of the world’s most sensitive maritime regions. The South China Sea remains a flashpoint because of overlapping territorial claims and the risk of miscalculation between rival governments.

The drills come as Washington and its regional partners have sought to increase joint readiness in response to China’s growing military presence and assertive operations in the area. Such exercises are also viewed as a signal of support for smaller states that rely on open sea lanes for trade and security.

While military encounters in the region continue to draw scrutiny, the stated purpose of the exercise is to reinforce coordination and help deter escalation. The latest maneuvers add to a steady pattern of multilateral drills intended to preserve maritime access and reduce the chance of conflict.