EU regulators have approved Google’s acquisition of the mobile phone maker Motorola Mobility without formal conditions, but it did warn that the giant should play fair in markets for smartphones and tablet computers.

Joaquin Almunia, the EU competition commissioner, did not impose any requirements for Google to complete the $US12.5 billion deal, which represents the internet search giant’s first foray into hardware.

But the deal comes at a time of heightened scrutiny by regulators over ownership of intellectual property governing computers and mobile communications. Almunia indicated in a statement that he would be watching the sector.

The decision “does not mean that the merger clearance blesses all actions by Motorola in the past or all future action by Google,” the statement said. He added that any action on “the question whether Motorola’s or Google’s conduct is compliant with EU antitrust law” would be taken separately.

Because US and European regulators seek to coordinate on major transactions, the US Justice Department, which is also reviewing the deal, could similarly approve the acquisition soon.

If the takeover wins global approval, it could give Google a portfolio of patents to serve as an impressive defense against infringement claims as it works to develop its popular Android operating system for mobile devices.

Almunia said he cleared the deal partly because Google’s business model has been to share its Android mobile operating system with other device makers in order to gain the widest user base, making it less likely that the company would restrict the use of Android solely to Motorola, which is a relatively minor player in Europe.

But Almunia expressed strong concerns about the way powerful technology companies had participated in setting the standards for the proper functioning of mobile devices like smartphones.

Owners of such patents could, “hold up competitors or even an entire industry to the detriment of consumers and innovation,” he said. “I can assure you that the commission will take further action if warranted to ensure that the use of standard essential patents by all players in the sector.”

Last week, Google wrote to standard-setting organisations around the world pledging to license Motorola patents on fair and reasonable terms if the deal succeeded.

Google promised to keep a cap on the fees it charges for licensing its technology and sought to outline the conditions under which it would sue companies for patent infringement.