The arbitrary seizure of foreign vessels by the United States constitutes a serious violation of international law, a Chinese foreign ministry spokesperson said on Monday.

Spokesperson Lin Jian made the remarks in response to a media query regarding the U.S. Coast Guard's seizure of an oil tanker on December 20 local time, with a White House official claiming the vessel belonged to a so-called "shadow fleet."

"China always opposes illegal unilateral sanctions that lack a basis in international law and are not authorized by the United Nations Security Council. It also opposes any actions that violate the purposes and principles of the UN Charter, infringe on the sovereignty and security of other countries, or constitute acts of unilateral bullying," Lin told a daily press briefing.

Venezuela has the right to independently develop mutually beneficial cooperation with other countries, and China believes that the international community understands and supports Venezuela's position on safeguarding its legitimate rights and interests, Lin added.