Russian gas giant Gazprom clinched a deal with European Union anti-trust regulators on Thursday to reform its pricing structure and allow rivals a foothold in eastern Europe, avoiding fines in a case that has dragged on for seven years.

Europe's competition enforcer said Gazprom's concessions allay concerns of market abuse, ending the EU's longest running anti-trust saga that began with dawn raids at 20 offices in 10 countries in 2011.

The EU's decision to accept Gazprom's offer has allowed it to escape fines of as much as 10% of its global turnover - an outcome that has angered Poland and other eastern EU countries that have sought a tougher line from Brussels.