Full coverage: The South China Sea Issue

China’s Ministry of National Defense says it has lodged an official complaint with Washington after a U.S. Navy guided-missile destroyer, the USS Decatur, sailed through Chinese territorial waters near Xisha islands without China’s permission.

After the U.S. warship entered Chinese waters, two Chinese navy ships issued a strong warning, demanding it leave.

China’s National Defense Ministry released an official response, announcing strong opposition to the military maneuver. In its statement, the ministry said the United States is well aware of China’s territorial sea baseline, and criticized Washington for trying to destabilize the region, just as the situation in the South China Sea is starting to improve.

The ministry added China has repeatedly urged the U.S. to respect China’s national sovereignty and security concerns, and warned the Chinese military will strengthen its surveillance, patrol, and defense capabilities in the region if needed.