The European Commission today said it has opened a formal investigation into whether Samsung is guilty of actions to “distort competition in European mobile device markets.”

According to the watchdog, the probe will assess if the South Korean giant has acted “abusively, and in contravention of a commitment it gave the European Telecommunications Standards Institute,” with regard to some of its standard-essential patent rights.

In 2011, Samsung took action in certain EU member states against competitors, alleging infringements of certain patent rights declared essential to the implementation of “European mobile telephony standards.”

The EC will now investigate if by doing so it has gone against an irrevocable commitment given to ETSI in 1998, to license the patents on fair, reasonable and non-discriminatory (FRAND) terms.

It said that a number of vendors made similar pledges, in line with the adoption of 3G standards for the European market. The Commission will “examine the case as a matter of priority,” but it has not stated the timeframe for its investigation. It also said that it “does not prejudge the outcome of the investigation.”

Separately, Reuters reports that Samsung lost a bid to overturn a German sales ban on its Galaxy Tab 10.1 device, following a complaint from Apple. The companies have a number of actions active in multiple markets.