The European Commission launched a probe Tuesday into charges that telecom firms block next-to-free Internet phone services to undermine competitors or degrade the quality of online videos.
With the proliferation of smart phones putting the Internet in the palm of consumers' hands, the European Union's executive arm asked a panel of national regulators to check that telecom firms are maintaining "net neutrality."
Neelie Kroes, the EU telecoms commissioner, warned that the investigation could lead to new rules if operators are found to be misleading consumers about the speed of their Internet services or blocking certain applications.
"Customers should not be led to believe they can access services that in practice are blocked or degraded. Nor should customers be hoodwinked about misleading claims about connection speeds," Kroes said.
The commission concedes that the management of Internet traffic is vital to prevent a congestion of Web networks with the massive use of heavy-data video services such as Google's YouTube website or the BBC's iPlayer.
But the commission wants to ensure companies are not managing Internet traffic to discriminate against competitors.
In a commission public consultation last year, users and content providers complained that mobile operators in six EU countries were blocking or charging extra for voice over Internet protocol (VoIP) services such as Skype.
"One UK operator is said to make Skype calls technically impossible in afternoons and evenings without warning the users," Kroes said, adding that customers should be informed about any restrictions.
She also said she was informed that some providers use so-called throttling techniques to slow down the traffic of video streaming provided by a competitor in order to degrade the quality of content.
"It is not okay for Skype and other such services to be 'throttled.' That is anti-competitive, it is not okay to rip off consumers on connection speeds," Kroes said.
The EU's executive commission said that while it "does not have evidence to conclude that these concerns are justified at this stage," a more "exhaustive fact-finding exercise" was necessary to clear any concerns.
The findings of the Body of European Regulators for Electronic Communications (BEREC) will be published by the end of the year.
Kroes said the commission intends to "publicly name operators engaging in doubtful practices and I sincerely hope that it will be a very short list."
The review will ensure that providers respect the principle of open Internet enshrined in new EU telecommunications rules that enter into force on May 25.
"If I am not satisfied, I will not hesitate to come up with more stringent measures which may take the form of guidance or even general legislative measures to achieve the competition and choice consumers deserve," Kroes said.
"Mark my words, if measures to enhance competition are not enough to bring Internet providers to offer real consumer choices I am ready to prohibit blocking of lawful services or applications."