Chinese navy seizes unmanned underwater US scientific vessel in South China Sea; US demands return of vehicle, US official told Reuters news agency. White House spokesman Josh Earnest confirms Navy warship navigated through South China Sea Philippines defence minister also said Chinese ships are no longer at Scarborough shoal, South China Sea. Chinese Ministry of Foreign Affaris said to take necessary measures to safeguard territorial sovereignty after US destroyer reported passing Xisha Islands in South China Sea, CCTV reported. He added that Chinese ships chased away American destroyer after it 'intruded' near Xisha Islands in South China Sea.