June 7 (Reuters) - Warren Buffett's Berkshire Hathaway ( BRK/A )

bought around 2.57 million shares of common stock in

Occidental Petroleum ( OXY ) over June 5-7, according to a U.S.

securities filing.

Buffett's company bought additional shares in Occidental's

common stock for more than $150 million and now owns about 250.6

million shares in the energy producer.

Occidental shares closed at $59.48 on Friday.

As of March, Berkshire owned a roughly 28% stake in

Occidental.

Occidental Petroleum ( OXY ) previously announced it had entered

into a joint venture with Berkshire Hathaway's ( BRK/A ) energy unit to

extract lithium in their geothermal facility in California.

(Reporting by Harshita Meenaktshi in Bengaluru)