Ukrainian businessman Dmitry Firtash has sold Hungarian natural gas wholesaler EMFESZ to Swiss-based RosGas AG, the Hungarian firm`s spokesman Igor Gallyas told national news agency MTI, Reuters reported.

EMFESZ, which supplies about 20 percent of the Hungarian market, announced last month that it would buy gas from RosGas in the future.

Istvan Goczi, managing director of EMFESZ, last month told Reuters that the firm expected to switch to the new supplier within a couple of days. He also said RosGas was controlled by Gazprom.

EMFESZ changed its supplier because Russian-Ukrainian gas agent RosUkrEnergo, its former supplier, had difficulties in getting gas out of storage in Ukraine.

RosUkrEnergo lost its role as a supply intermediary between Russia and Ukraine in January and Ukrainian authorities took over 11 billion cubic metres of stored gas, which RosUkrEnergo says still belongs to it.

EMFESZ imports about 3 billion cubic metres of gas to Hungary per year.