WASHINGTON - U.S. antitrust regulators approved Australian packaging group Amcor's (AMC.AX) purchase of mining company Rio Tinto's (RIO.AX)(RIO.L) Alcan packaging unit, the Federal Trade Commission said on Tuesday.

The European Commission approved the $2 billion deal on December 15 on the condition that the companies sell the major part of Amcor's business in pharmaceutical flexible packaging.

Amcor Chief Executive Ken MacKenzie is making his first big acquisition after four years of fixing, closing and selling businesses.

Rio Tinto, the world's second largest miner, is selling assets to boost a balance sheet damaged by its takeover of Alcan at the peak of the commodities boom.

(Reporting by Diane Bartz; Editing by Derek Caney)