The regulator is also examining whether Google services are prioritized on Android phones.
The Japan Fair Trade Commission said it is examining whether Google made agreements with Android smartphone makers to share search ad-related revenue on the condition that the device manufacturer does not install a rival search engine.
Japan's competition watchdog on Monday said it is investigating Alphabet -owned Google for alleged antitrust law violations in regards to its search practices on mobile platforms, ramping up regulatory pressure on the U.S. technology giant.
In response, Google said Android is an "open-source platform that has enabled a diversity" in partners and device manufacturers.
The EU said Google unfairly favored its own services by forcing smartphone makers to pre-install Google apps Chrome and Search in a bundle with its app store, Google Play.
Persons:
CNBC's Lauren Feiner
Organizations:
Google, Japan Fair Trade Commission, Japan FTC, CNBC, European Union, EU, U.S . Department of Justice
Locations:
Japan, EU, U.S