EU antitrust chief expected to charge Google on Wednesday: sources

European Competition Commissioner Margrethe Vestager looks on as she addresses a news conference in Brussels, Belgium, January 11, 2016. REUTERS/Francois Lenoir

BRUSSELS (Reuters) - Europe’s antitrust chief is expected to hit Google on Wednesday with anti-competitive charges concerning its Android mobile phone operating system, two people familiar with the matter said.

EU charges would open up a second front in the regulatory battle between the European Commission and Google, exposing the world’s most popular Internet search engine to the risk of hefty fines and radical changes to its business practices.

Google is already battling EU charges of promoting its own shopping service in Internet searches at the expense of rival products, a case which has dragged on since late 2010.

With estimated revenues of $11 billion from ad sales on Android phones with Google apps such as Maps, Search and Gmail, the stakes are high for the U.S. tech giant.

European Competition Commissioner Margrethe Vestager said on Monday she was concerned Google may be favoring its apps by requiring phone makers and network operators to preload them, thus stifling competition from rival apps.

European Commission spokesman Ricardo Cardoso and Google declined to comment.

Reporting by Foo Yun Chee; editing by David Clarke