Japan’s competition watchdog said it is investigating Google for antitrust violations related to the company’s search practices on mobile platforms, intensifying regulatory pressure on the US tech giant, CNBC reports.

Japan’s Fair Trade Commission also said it was examining whether Google had entered into agreements with Android smartphone makers to share ad revenue on the condition that the device maker did not install a rival search engine.

On top of all this, it will also check if Google services are prioritised on Android phones.

Google was quick to state that Android is an “open source platform that has enabled diversity” from partners and device manufacturers.

The Japanese commission will seek public input, including from third parties, until 22 November.

“Its openness and flexibility ensure that users always have a choice to customize their devices to suit their needs, including the way they browse and search the internet, or download apps,” a Google spokesperson told CNBC via email.

Android is the world’s largest mobile operating system, accounting for a roughly 80% market share of smartphones.

Google seems to have suffered a number of breaches in recent years. Some of Google’s business practices in relation to Android have come under scrutiny from regulators around the world.

Google seems to have suffered a number of breaches in recent years. Some of Google’s business practices in relation to Android have come under scrutiny from regulators around the world. In 2018, the European Union fined Google a record €4.34 billion ($4.6 billion) for abusing Android’s dominant position.

The EU said Google had unfairly favoured its own services by forcing smartphone makers to pre-install Google Chrome and Search apps bundled with the Google Play app store.

After an appeal by Google, the EU court reduced the fine imposed on Google last year.

During the trial, which began last month, the U.S. Department of Justice alleged that Google violated antitrust law through exclusive agreements with mobile phone and browser makers to make its search engine standard for consumers.

According to CNBC, this ongoing proceeding is the largest US tech antitrust trial in decades.