"The response filed today addresses all aspects of the Statement of Objections and shows why we believe the European Commission's allegations are based on an incorrect methodology," Gazprom said in a statement.

"In particular, when it comes to Gazprom's alleged excessive pricing, our response provides evidence and data to show why the Commission's conclusions are both economically and legally unfounded," it said.

(Reporting by Barbara Lewis and Foo Yun Chee)