By Aleksandras Budrys and Polina Devitt

MOSCOW, April 17 (Reuters) - Billionaire Suleiman Kerimov has agreed to raise his stake in Russian miner Polyus Gold to 37 percent in a deal ending an asset split between two of Russia's richest men, two sources close to the deal said.
The sources, speaking on Friday on condition of anonymity, declined to provide more details of the deal and said it was subject to regulatory approval.
Vedomosti business daily, citing two unnamed sources, said Kerimov had spent a total of $1.3 billion building up his stake. He bought 15 percent of Polyus, Russia's top gold miner, on April 15 after acquiring 22 percent last month, the paper said.
Kerimov bought the stakes in Russia's largest gold producer from billionaire Vladimir Potanin.
The deal has still to be approved by the Federal Anti-Monopoly Service and the Commission on Foreign Investments, chaired by Prime Minister Vladimir Putin, as the deal is between offshore companies.
Kerimov's investment vehicle, Nafta Moskva, and Potanin's Interros company declined to comment. Polyus Gold also declined to comment.
Industry sources told Reuters in March that Kerimov had bought a 20 percent stake in Polyus from Potanin and planned to acquire Potanin's remaining 17 percent.
Polyus was the last company under the joint control of Potanin and Mikhail Prokhorov, the former business partners who announced more than two years ago they were splitting their varied assets in mining and finance.
Prokhorov, who is chairman of Polyus, remains a shareholder.
Analysts welcomed the deal, saying it resolved a long-lasting shareholder conflict between Potanin and Prokhorov.
"Kerimov is reportedly a Prokhorov ally, and therefore we would expect him to support Prokhorov in development of the company," UniCredit said in a note.
Troika Dialog said the sale of the stake at $1.3 billion would signal a 60 percent discount to the current price.
"It is logical for Interros to monetise its stake in Polyus Gold at this stage in some shape or form, providing much needed cash to the holding, especially considering that Mikhail Prokhorov's Onexim Group, with its 30 percent stake, fully controls the operations of the gold company," it said.
Gold, often sought as a safe-haven alternative to equities and currencies during economic strife, has performed better than other metals during the global financial crisis.
Polyus produced about one fifth of Russia's gold last year.

(Editing by David Cowell) Keywords: GOLD RUSSIA/POLYUS (robin.paxton@reuters.com; +7 495 775 1242; Reuters Messaging: robin.paxton.reuters.com@reuters.net)