LONDON, March 7 (Reuters) - Russian hydropower group EN+ is reviewing options for aluminum giant Rusal, in which it is majority shareholder, including turning its international business into a separate entity.

Western governments are tightening sanctions on Moscow for its invasion of Ukraine, triggering a disposal of Russian assets and investments worth tens of billions of dollars.

EN+ said on Monday that its strategic review of Rusal, in which it owns nearly 57%, was at a preliminary stage and any moves would be subject to "further consideration" as well as talks with regulators and stakeholders.

Rusal,, the world's largest aluminum producer outside China, is in the process of spinning off its higher-carbon assets located in Russia into a separate entity.

Major En+ shareholders are Russian tycoon and Rusal founder Oleg Deripaska, who has a stake of around 45%, and commodity trader and miner Glencore.

Glencore, which last week said it is reviewing its 10.5% equity stake in En+, declined to comment on Monday's announcement by the group.

The London Stock Exchange last week suspended the trading of global depository receipts (GDRs) of En+ and several other Russia-based companies while ratings agency Fitch downgraded 26 Russian natural resources companies to reflect increased financial risks.

Russia produces about 6% of the world's aluminum and accounts for about 3.5% of copper supplies. It is also a major producer of natural gas used to generate electricity that powers energy-intensive aluminum smelters.

"Right now, any metal with a Russian tag on it is considered toxic," said Julius Baer commodities analyst Carsten Menke.

Wood Mackenzie said last week that Rusal had halted shipments of aluminum raw ingredient alumina from its 1.75 million tonne a year refinery located close to the port of Mykolaiv in Ukraine.

Supply concerns and high energy prices pushed prices for aluminum to a record above $4,000 per tonne.

EN+ also said on Monday that its chairman Gregory Barker will step down after more than four years in the role and will be replaced by Christopher Bancroft Burnham.

Members of the boards of Russian-based companies such as Evraz, and Polymetal have also stepped down since Russia's invasion of Ukraine.

(Reporting by Yadarisa Shabong in Bengaluru and Zandi Shabalala, additional reporting by Clara Denina, editing by Alexander Smith)