WASHINGTON (Reuters) -The United States has imposed tariffs on imports of one-kilo gold bars, the Financial Times reported on Thursday, citing a letter from Customs Border Protection.

The letter - dated July 31 - said one-kilo and 100 ounce gold bars should be classified under a customs code subject to levels, according to the newspaper, which added that the move could impact Switzerland, the world's largest refining hub.

(Reporting by Jasper Ward)