Gazprom and the European Commission need further talks to assess the Russian gas giant’s compliance with EU competition law, they said after a meeting on 29 May in Brussels.

Gazprom’s deputy chief executive, Alexander Medvedev, met Competition Commissioner Margrethe Vestager to discuss concessions aimed at ending a six-year-long investigation into Gazprom’s alleged anti-competitive practices in the supply of gas to Eastern and Central Europe.

“We had a very productive discussion today with Commissioner Vestager and her team. We have agreed to hold further talks at technical level in the coming weeks,” Medvedev said in a statement.

To meet EU requests, Gazprom offered to let clients renegotiate decades-long, oil-indexed contracts, with prices linked to benchmarks such as European gas market hubs and border prices, including in Germany.

The concessions made by Gazprom are now being tested to assess their impact in the market. Some rivals, such as state-run Polish oil and gas company PGNiG, are calling for the offer to be turned down and Gazprom to be fined, according to Reuters.

“Further contacts with Gazprom are required to address the results of the market test and ensure the Commission’s objectives are met,” a spokesman for Vestager said after the meeting.

Medvedev said he hoped the new talks could conclude “the settlement procedure in the near future”.

On 13 March, the Commission published Gazprom’s commitments to end a five-year antitrust case and avoid heavy fines.

The case was opened after Lithuania blew the whistle on Gazprom’s anti-competitive practices.