The European Commission said Thursday it was dropping an investigation into five huge European telecoms companies over possible collusion in setting industry standards for mobile phones.

The Commission said it had been in contact last year with Deutsche Telecom, France Telecom, Spain's Telefonica, Vodafone and Telecom Italia, plus mobile sector association GSMA, about the way standards for future mobile communications services were developed.

The aim was to ensure that standards were "not being used strategically" to the disadvantage of other companies, it said.

The five companies have since transferred their work on standardisation to GSMA and other industry associations, which "allows more stakeholder participation," it said in a statement.

"It is a positive step that reduces the risk of standard setting work affecting competition negatively. Therefore, the Commission is closing its preliminary investigation."

It added that it would "remain watchful of how standardisation processes evolve in this sector."