EU antitrust regulators plan to order Alphabet's Google to stop paying financial incentives to smartphone makers to pre-install Google Search exclusively on their devices and warned the company of a large fine. Reuters reports that an EU document showed was sent to complainants last week for feedback. Google received a copy in April in which the European Commission accused it of using its dominant Android mobile operating system to shut out rivals.

The so-called statement of objections, says that the U.S. technology giant should halt payments or discounts to mobile phone manufacturers in return for pre-installing Google's Play Store with Google Search.

The regulators also want to prevent Google from forcing smartphone makers to pre-install its proprietary apps if this restricts their ability to use competing operating systems based on Android.

The Commission's investigation followed a complaint by FairSearch, a lobby group supported by companies that want to ensure they are not disadvantaged by search engine market dominance, in March 2013.

A possible Google fine could be based on revenue generated from AdWords clicks by European users, Google Search product queries, Play Store apps purchases and AdMob's in-app advertisements.

Separately, the Commission is investigating whether Google favors its own shopping service over those of rivals, and could also fine it in that case.