EU nations agreed on Dec. 7 to allow the European Commission to vet their oil and gas deals with third countries, like Russia, to guard against anti-competitive practices and supply disruptions.

Under the new rules, proposed by the commission in February, EU nations will have to allow Brussels to review intergovernmental agreements on oil and gas deals before they sign them. Electricity deals will only have to be reported to the commission after they are completed.

Overcoming resistance from member states wary of ceding sovereignty, the EU executive welcomed the deal with the bloc's 28 nations and the European Parliament as a boost in its drive for a single EU energy market and to curb reliance on Russian gas.

Concerns in Europe over the EU's reliance on Russia for over one-third of its gas needs have grown since pricing disagreements between Moscow and Kiev disrupted gas supplies and in the wake of Russia's seizure of the Crimea region from Ukraine in March 2014.

The European Commissioner for Climate Action and Energy, Miguel Arias Canete, said the new rules will "guarantee that no energy deal jeopardizes the security of supply in an EU country, or hampers the functioning of the EU's energy market."

The commission said it needs the new rules because about one-third of 124 energy-related intergovernmental agreements in Europe fail to comply with EU law, and contesting them has proved difficult.

The commission wants to avoid a repeat of the legal headaches it faced when it ruled that Gazprom's planned South Stream Pipeline under the Black Sea ran counter to EU competition law, challenging a web of bilateral deals Russia cut with Eastern European states.