Intellectual property rights could be unfairly used by firms against their rivals, EU regulators have said.
The European Commission earlier this month asked Apple and Samsung for details on patents used as standards in the mobile telephone industry after the two firms became locked in a smartphone patent war involving more than 20 cases in 10 countries.
"We requested information from both Apple and Samsung. We have not yet received the answers," said EU Competition Commissioner Joaquin Almunia.
"We need to look at this because IP rights can be used as a distortion of competition but we will need to look at the answers.
"In particular, in the IT sector, it is obvious it is not the only case. Apple and Samsung is only one case where IP rights can be used as an instrument to restrict competition.
"Standardisation and IP rights are two instruments that in this new IT sector can be used as a tool to abuse."
This is the first time that the EU's antitrust chief has publicly voiced his concerns over patent wars in the mobile telephony sector.
Analysts have said companies can gain an advantage over their opponents with legal bans on rival products.
Samsung's Galaxy tablet is the hottest competitor to Apple's iPad which dominates tablet sales worldwide.
Apple is also involved in patent disputes with Taiwan's HTC and Motorola.
The Commission can fine companies up to 10 per cent of global turnover for breaching EU rules.