LONDON (Reuters) - Russian metals billionaire Suleiman Kerimov has bought a stake of just under 3 percent in London-listed ENRC (>> Eurasian Natural Resources Corporation), the embattled Kazakh miner facing a potential buyout led by its founders.

According to a regulatory filing, Kerimov bought a 2.86 percent stake - or almost 37 million shares - on April 29, when that holding would have been worth roughly 100 million pounds.

He raised that to 2.96 percent the following day, according to a filing on Wednesday, buying an additional 1.3 million shares at just over 271 pence each.

A Kremlin-connected tycoon from Russia's southern province of Dagestan, Kerimov is a major investor in a range of Russian companies, with holdings including the single largest stake in Polyus Gold (>> Polyus Gold International Ltd), Russia's biggest gold miner, and holdings in fertiliser group Uralkali (>> Uralkaliy OAO) and homebuilder PIK (>> Gruppa kompaniy PIK OAO).

He has also been an opportunistic investor in stocks outside Russia.

ENRC shares are trading close to their 2008 lows after being buffeted by cooling metals prices, corruption investigations and boardroom scuffles. They were trading at just under 268p by 1120 British Time, down 2.5 percent on the day.

Kerimov's investment vehicle, Nafta, declined to comment.

ENRC's trio of founders said last month they were considering a buyout of minority shareholders in the group. They have until May 17 to declare whether or not they intend to bid.

(Reporting by Clara Ferreira-Marques; Editing by David Holmes)