Google faces fresh EU anti-competition charges, this time targeting the search engine giant's advertising business, sources close to the matter told AFP on Tuesday.

Margrethe Vestager, the powerful EU Competition Commissioner, could open two new in-depth investigations against Google as early as August, the sources said on condition of anonymity.

The first case would involve the Silicon Valley giant's lucrative advertising business, while the second would deepen an existing case targeting online shopping practices.

The EU in 2014 accused Google of abusing its dominance in the Internet search market to steer European consumers to its own shopping service.

A spokesman for the European Commission refused to comment on the report.

In April, Brussels also charged Google with abusing the dominance of its Android mobile phone operating system. The Android operating system accounts for about 80 percent of the world market for mobile phones, far ahead of Google's closest rival, Apple.

The EU has accused Google of obstructing innovation by giving unfair prominence to its own Android apps, especially its search engine, in deals with mobile phone manufacturers such as Samsung and Huawei.

If found at fault, Google risks a fine equal to up to 10 percent of worldwide global sales for one year, which would amount to a $7.4 billion on the basis of 2015 revenues.