The European Commission announced the investigation on Tuesday, saying there were concerns that Gazprom may be abusing its "dominate market position in upstream gas supply markets." Specifically, three suspected anti-competitive practices in Central and Eastern Europe are being investigated.

"First, Gazprom may have divided gas markets by hindering the free flow of gas across [EU] member states," a statement from the commission read. "Second, Gazprom may have prevented the diversification of supply of gas. Finally, Gazprom may have imposed unfair prices on its customers by linking the price of gas to oil prices."

The Commission said that if such behavior was established to be taking place, it may constitute a restriction of competition, which could have lead to higher prices.

The EU imports natural gas to meet 80 percent of its demand, and about a third of that comes from Russia. The European Commission can levy fines of up to 10 percent of the annual turnover of a company that violates its anti-trust policies.

mz/ipj (AFP, dpa)