The first stage of the modernization of the Ukrainian gas transport system (GTS) will cost $3-4 billion, Ukrainian Energy and Coal Industry Minister Yuriy Prodan has said.

"About $3-4 billion will be required for the first stage of the modernization," he told reporters in Kyiv on Wednesday.

He recalled that Ukraine had sent a proposal for the joint operation and modernization of its gas transport system to companies in the European Union and the United States.

Prodan said that formal negotiations were not currently being conducted and that it was still impossible to say which form of the joint operation of the gas transport system will be carried out.