The rise follows a restriction imposed by Britain from Dec. 15 on UK entities and individuals taking physical delivery of Russia-made base metals, part of wider sanctions on Moscow for its war in Ukraine.
"With regard to recent UK Government sanctions, the LME is actively monitoring for market orderliness in respect of Russian metal," the LME, the world's oldest and largest metals market, said in a separate comment.
The exchange added that "Russian metal continued to flow through the warehousing network during December".
The amount of Russian primary aluminium stocks on LME warrant rose to 338,375 metric tons in December from 154,775 in November, data published by the LME showed.
On-warrant aluminium inventories are those which have not been earmarked for removal and are available to the market. Warrants are title documents conferring ownership of metal.
The high share of Russian-origin metal in LME inventories has been a concern for some producers, which compete with Russia's Rusal, and some Western consumers who have been avoiding the Russian metal since Moscow's invasion of Ukraine in 2022.
(Reporting by Polina Devitt; Editing by Pratima Desai and Jan Harvey)
