The Russian-flagged tanker, operated by Russian shipping group Sovcomflot's (SCF) Dubai-based subsidiary SCF MGMT, is carrying about 700,000 barrels of Russian Sokol crude.

It is the fourth U.S.-sanctioned tanker to dock at Chinese ports this month to clear a backlog of Russian Sokol crude stored on ships.

However, the previous ships - Liteyny Prospect, Krymsk and Nellis - had docked during temporary waivers of sanctions from U.S. measures related to the Ukraine war.

Officials at Qingdao port did not immediately respond to a request for comment. China's General Administration of Customs could not immediately be reached for comment.

On Nov. 16, the U.S. Treasury's Office of Foreign Asset Control (OFAC) imposed sanctions on three tankers, including NS Century, for violating a $60-per-barrel price cap on Russian crude oil exports. It also issued general licences allowing the offloading of crude oil, or other cargoes, from the three vessels until Feb. 14.

United Arab Emirates-based Gallion Navigation Incorporated is the registered owner of the NS Century, according to OFAC. Gallion could not immediately be reached for comment.

The G7-led price cap on Russian crude, imposed in December 2022, aims to reduce how much money Russia has available for its war in Ukraine by allowing Western-supplied insurance and other services only on cargoes priced below $60 a barrel.

Beijing has said that it opposes unilateral sanctions and that China's normal trade deserves respect and protection.

China has become the top lifter of light sweet Sokol crude after shipments to India fell following payment and shipping issues because of to sanctions.

Sokol oil is a low-sulphur, light grade exported from the De Kastri terminal on Russia's Sakhalin island by Sakhalin-1 LLC, controlled by oil giant Rosneft.

(Reporting by Florence Tan; Additional reporting by Andrew Hayley in Beijing. Editing by Gerry Doyle)

By Florence Tan