Korea's antitrust watchdog on Thursday said it conducted an investigation into Google Inc. over allegedly forcing smartphone makers to use its operating system in their handsets.

The Fair Trade Commission conducted the inspection of Google's local headquarters in southern Seoul last week, two years after the commission acquitted the global giant of the same charge.

In 2013, after two years of investigation, the FTC acquitted Google of hurting fair market competition by obliging mobile phone makers to preload its search engine when offering its Android operating system to those producers.

The FTC had reviewed the case and came to the conclusion to dismiss the charges, saying that Google's preload requirement does not restrict market competition as the market share remains around 10 percent.

Industry sources said the FTC began looking into the allegations again after the European Union brought charges against Google for similar anticompetitive behaviors earlier this year. (Yonhap)