By Siyi Liu

SINGAPORE (Reuters) - A tanker subject to the new U.S. sanctions is discharging Russian oil at a port operated by Shandong Port Group in east China, shipping data on LSEG Eikon showed on Thursday.

The tanker is the first since last week's sanctions announcement to discharge in Shandong province where many of China's independent refineries that have been big importers of Russian crude are based.

It will be monitored closely by those in the industry anxious to know how strictly the measures will be implemented.

The sanctions include a grace period exempting cargoes loaded before Jan. 10 and unloaded before March 12, traders said, but the industry still halted some shipments as they assessed their risks.

Shandong Port Group was not available for comment after normal office hours.

The Panama-flagged crude oil tanker Mermar docked on Wednesday at Longkou port in the city of Yantai. It had floated since Saturday, the LSEG data showed.

The data also showed the Aframax-sized tanker carried 80,000 metric tons of (600,000 barrels) Russian ESPO Blend crude that was loaded on Jan. 6 from Kozmino port on Russia's east coast.

The Mermar was among 183 ships designated by the Biden administration on Friday in an announcement that disrupted supply from the world's No. 2 producer to China and India and reduced ship availability.

The U.S. Office of Foreign Assets Control said the Mermar had made a port call in a Russian port where oil has consistently traded well above a $60 price cap imposed by the West to try to curb Russia's oil revenues.

The tanker is considered part of Russia's shadow fleet that it has used until now to skirt sanctions. Its registered owner Merluza Group has also been placed under restrictions by the new measures.

Prior to the U.S. sanctions announcement, Shandong Port Group had banned U.S.-sanctioned tankers from calling into its ports in the eastern Chinese province.

(Reporting by Siyi Liu in Singapore; Editing by Florence Tan and Barbara Lewis)