MOSCOW (Reuters) -A Russian court on Wednesday postponed legal proceedings by more than nine months in a $2.9 billion lawsuit filed by Russia's Rosatom against Finland's Fortum and Outokumpu, court filings showed.

State-controlled nuclear energy firm Rosatom is seeking 227.8 billion roubles ($2.9 billion) in compensation for losses over the termination of a contract for the Hanhikivi-1 nuclear power plant in Finland, court documents and a Rosatom statement showed in May.

A hearing scheduled at the Moscow City Arbitration Court for Wednesday morning was postponed until March 16, 2026, court filings showed, without giving further details. Rosatom, Fortum and Outokumpu had no immediate comment.

Rosatom and its former Finnish partners have been locked in dispute over the cancelled contract since May 2022. The Finnish side terminated the project soon after Moscow launched the conflict in Ukraine, citing significant delays and political risks.

Rosatom in May said it was seeking compensation for losses caused by what it called the unlawful termination of the EPC contract to build the plant, violations of the shareholder agreement and other contractual disputes.

Outokumpu has said it was never a direct party to the EPC agreement or any other agreement with any Rosatom company related to the Hanhikivi-1 project. Fortum said in May that the International Chamber of Commerce's decision that Rosatom's subsidiary could not make Fortum a party to proceedings was final.

The contract to build the 1.2 gigawatt plant with investments estimated at 6.5-7 billion euros was signed in 2013 with Fennovoima, a joint consortium in which Finnish stakeholders including Fortum, Outokumpu and SSAB originally controlled two thirds through a joint venture, and the Russian side held one third.

After the project's termination, Fennovoima ceased all its operations and is only engaged in legal disputes.

($1 = 78.6000 roubles)

(Reporting by Anastasia Lyrchikova; additional reporting by Essi Lehto in Helsinki; Writing by Alexander Marrow; Editing by Alexandra Hudson)