DUBAI - Saudi Arabia's King Salman will begin a visit to Russia on Thursday at the invitation of President Vladimir Putin, Saudi state news agency SPA said, the Gulf ruler's first trip to Moscow since becoming king in 2015.

During the visit the two countries plan to set up a $1 billion fund to invest in energy projects as part of efforts by two of the world's biggest oil producers to expand cooperation, Russian Energy Minister Alexander Novak said earlier on Monday.

SPA said the two leaders would discuss bilateral and regional issues, but gave no details.

Saudi Arabia, the biggest oil producer in the Organization of the Petroleum Exporting Countries, and Russia helped forge a deal between OPEC and other producers to cut output by 1.8 million barrels per day from January to lift crude prices.

(Reporting by Sylvia Westall; Editing by Gareth Jones) ((sylvia.westall@thomsonreuters.com; Dubai Newsroom +971 56 216 6204; Reuters Messaging: sylvia.westall.thomsonreuters.com@reuters.net))