WASHINGTON, Jan 24 (Reuters) - U.S. Attorney General Merrick Garland said on Tuesday, after the Justice Department filed an antitrust lawsuit against Alphabet's Google, that the Big Tech company has sought to defeat its rivals in the online advertising business using anticompetitive tactics for 15 years.

Garland added that as a result of Google's practices the United States has suffered as an advertiser, overpaying for ads. (Reporting by Chris Sanders and Diane Bartz)