The Korea Fair Trade Commission (KFTC) disclosed the investigation in a brief statement. It did not say what the probe was about nor any potential antitrust violations. The KFTC apparently raided Google's Seoul headquarters in July.

The antitrust body's statement came after a local media report said the KFTC had decided to clear Google of anticompetition charges involving the pre-loading of the company's apps on smartphones running on the Android operating system. So it probably wants to make it clear that no thumbs have been raised for the search engine yet.

While it wasn't clear whether the probe would lead to any formal charges, the investigation is another regulatory headache for Google. The firm was fined $6.8 million in Russia on Thursday and faces multiple European Union antitrust charges.

The KFTC has investigated Google before. In 2013, the regulator cleared Google of wrongdoing following a probe into whether the company hurt competition by forcing smartphone makers using Android to pre-load its search engine on the handsets.