China expressed opposition on Monday to the United States' move to add a China-based oil terminal operator into its sanctions list targeting Russian oil export, calling it "illegal unilateral sanctions" and "long-arm jurisdiction".

Foreign Ministry spokesman Guo Jiakun made the remarks after the US announced on Friday to include the Shandong United Energy Pipeline Transportation Co Ltd on its sanctions list for allegedly providing support for Russian's largest shipping operator Sovcomflot, which Washington said helps facilitate Moscow's oil export.

China always opposes the US move to abuse the concept of national security, disrupt and restrict normal trade cooperation between other countries, Guo told a daily news conference.

"China always opposes illegal unilateral sanctions and long-arm jurisdiction that have no basis in international law and are not authorized by the United Nations Security Council," he said.

Also on Monday, the spokesman blasted the Philippines' accusations of China's activities in the South China Sea, urging the country to stop malicious hype.

Manila said on Monday it has lodged a protest over the presence of China Coast Guard, militia and navy in its "exclusive economic zone".

Guo stressed that CCG's patrol and law enforcement activities are reasonable, lawful and beyond reproach.

China's sovereignty and related rights in the South China Sea have been formed over a long historical process, which have historical and legal evidence and are in accordance with international law and practice, he said.