The European Commission officials have searched offices of gas companies in ten European states, including subsidiaries of Russian gas giant Gazprom.
"Commission officials undertook unannounced inspections at the premises of companies active in the supply, transmission and storage of natural gas in several member states," the commission, which is vested with antitrust powers in the EU, said.
"The Commission has concerns that the companies concerned may have engaged in anticompetitive practices in breach of EU antitrust rules or that they are in possession of information relating to such practices," a commission statement reads.
A spokesman for Gazprom Germania, the gas giant's German subsidiary, said European Commission officials conducted searches in the company's office in Berlin.
A German weekly business news magazine, Wirtschaftswoche, said the company, among other things, was suspected of price collusion.
Premises of Vemex sro, a Gazprom group member in the Czech Republic, were also searched.
Sergei Kupriyanov, a spokesman for Gazprom, said the company will make an official statement on Wednesday.