Berkshire Hathaway Inc. is still looking for major acquisitions to expand its businesses, the conglomerate's CEO Warren Buffett said in his eagerly awaited annual letter to shareholders on Saturday.

"My task is clear, and I'm on the prowl," Buffett said in the 22-page letter. However, he did not specify what sort of assets Berkshire Hathaway might be seeking.

(Reporting by Ben Berkowitz; Editing by Eric Beech)