BEIJING, July 3 (Xinhua) -- China resolutely opposed the illegal entry of a U.S. missile destroyer into China's territorial waters off the Xisha Islands, calling it "a serious offence," a military spokesperson said Monday.
Wu Qian, spokesperson for China's Ministry of National Defense, said in a statement that China had dispatched military vessels and fighter planes to warn the U.S. vessel.
Earlier Sunday, the missile destroyer USS Stethem trespassed into China's territorial waters off the Xisha Islands.
The U.S. has seriously undermined mutual strategic trust and the political atmosphere for the development of mutual military relations, Wu said.
It has also threatened safety of front-line soldiers and damaged regional peace and stability gravely, the spokesperson said.
The Chinese military will strengthen its defense ability according to the level of threat to national security and resolutely safeguard national sovereignty and security, Wu said.