A People's Liberation Army Navy fleet — including the aircraft carrier Liaoning, submarines, vessels and fighter jets — takes part in a review in the South China Sea on Apr. 12, 2018.

The United States called on China on Saturday to stop "bullying behavior" in the South China Sea and said it was concerned by reports of China's "provocative actions" aimed at offshore oil and gas developments in the disputed waters.

Three regional security sources said on Friday that a Chinese government survey ship was tagging an exploration vessel operated by Malaysia's state oil company Petronas in those waters.

Earlier in the week, when the survey ship the Haiyang Dizhi 8 was off Vietnam, a Chinese foreign ministry spokesman had said the ship was conducting normal activities and accused U.S. officials of smearing Beijing.