U.S. military officials say a Chinese warship nearly collided with an American Navy guided missile cruiser operating in international waters.

U.S. Pacific Fleet says it happened Dec. 5 in the South China Sea, and that the USS Cowpens maneuvered to avoid the collision.

The State Department has raised the matter at a high level with the Chinese government.

The incident comes amid heightened tension over China's growing assertiveness in the region.

Despite strenuous objections from Washington, Beijing recently declared a new air defense zone over parts of the East China Sea.

Pacific Fleet says it's not uncommon for navies to operate in close proximity and that's why it is paramount they all follow international standards for maritime "rules of the road."