By Margit Feher

BUDAPEST--The two companies in charge of the natural gas supply systems of Hungary and Ukraine signed an agreement last week that will allow reverse gas flows between the two neighboring countries, the Hungarian company said Friday.

A significant amount of the natural gas exported from Russia to Europe crosses through Ukraine, despite the ongoing tensions in the region. Reverse flows from the European Union--in this case from Hungary--to Ukraine are a key element of the EU's strategy to increase its Eastern neighbor's energy supply security, FGSZ Foldgazszallito Zrt., said.

FGSZ, a member of the Hungary-based oil and gas company MOL Nyrt. (MOL.BU) group, signed the contract with Ukrtransgaz, a unit of Ukraine's Naftogaz.

Under the agreement, the capacity of the gas hub at the border crossing at Beregdaroc will be 6.1 billion cubic meters of gas a year flowing from Hungary to Ukraine, and 26 billion cubic meters a year in the opposite direction. Beregdaroc is a Hungarian village close to the border with Ukraine.

The new agreement, the first of its kind in the EU, is in line with EU industry standards and replaces previous, temporary deals.

The European Commission, the EU's executive, intends it to serve as a basis for similar agreements Ukraine may sign with other EU members, FGSZ said in a news release.

Further development is necessary on both sides of the border to prevent disruption in the Hungary-to-Ukraine direction, FGSZ said. Conditions for this will still need to be provided by the regulatory authorities and the firms involved, the release states.

Write to Margit Feher at margit.feher@wsj.com; Twitter: @margitfeher

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