Google is hit with $1.7 billion fine by EU regulators for blocking advertising rivals - the tech giant's third punishment in two years

European Union regulators have hit Google with a $1.68 billion (1.49 billion euro/£1.28billion) fine for abusing its dominant role in online advertising.

The EU's competition commissioner, Margrethe Vestager, announced the results of the long-running probe of Google's AdSense advertising business case at a news conference in Brussels on Wednesday.

It's the third time the commission has slapped Google with an antitrust penalty, following multibillion-dollar fines resulting from separate probes into two other parts of the Silicon Valley giant's business.

In 2017, she slapped Google with a $2.84bn (£2.1bn / €2.42bn) fine in a case involving its online shopping search results.

The European Commission opened the most recent case against Google in 2016, accusing the search engine of preventing third parties using its AdSense product from displaying search advertisements from Google's competitors.

It said that Google, which at that time had held 80 percent of the European market for search advertising intermediation over the previous ten years, had kept its anti-competitive practices for a decade.

In response, Google changed the conditions in its AdSense contracts with large third parties, giving them more leeway to display competing search ads.

The AdSense case may not be end of Google's EU antitrust woes.

EU antitrust enforcers have asked Google's rivals if it unfairly demotes local search competitors, according to a questionnaire seen by Reuters, a move which could lead to a fourth case.

Online mapping services and others could also soon be in the spotlight.