MOSCOW, September 27. /TASS/. Russian President Vladimir Putin talked to Prime Minister of Bulgaria Boyko Borisov on the phone, discussing issues including energy cooperation, according to the Kremlin press service.

"The telephone conversation between Russian President Vladimir Putin and Prime Minister of Bulgaria Boyko Borisov was held upon an initiative of the Bulgarian side. Issues of bilateral cooperation in trade, economic and energy spheres were discussed," the press service said.

As was clarified by the press service of the Government of Bulgaria, Borisov told Putin that "the Bulgarian government has made specific steps to pay the debts of the Bulgarian National Electricity Company to Russian Atomstroyexport, which by September 19 amounted to 628 mln euro." "This sum includes the principal of loan, costs and interest accrued on the amount of the debt," the press service said, adding that this issue has been already discussed in the National Assembly of Bulgaria.

The press service noted, "Bulgaria insists on revising the interest conditions set by Atomstroyexport. Our goal is to solve problems between the two companies and put future joint energy projects on a stable foundation."

According to the Bulgarian side, the project of Balkan gas hub was also in the focus of the conversation. Construction of the gas hum is undergoing preparations on the territory of Bulgaria. "Preparation of the trilateral meeting between Bulgaria, Russia and the European Commission was discussed. The meeting will help to clarify technical, economic and legal details in respect to the project," the press service said.

It is planned that the experts from Bulgartransgaz will introduce the Russian side to the developed business model for the gas hub.

The press service also noted that leaders "expressed their satisfaction with the increasing number of Russian tourists", their number growing by 40% in Bulgaria this summer against last year’s figures.

The last time Putin and Borisov spoke on the phone in early August, then they, in particular, agreed to intensify cooperation between the two countries in the framework of the Russian-Bulgarian intergovernmental commission on economic, scientific and technical cooperation. The meeting of co-chairs of the commission was held in Varna, Bulgaria on September 16.

Unimplemented project of the South Stream gas pipeline is one of the largest bilateral projects in the energy sector. The European Parliament has recommended Bulgaria to abandon the project. At the end of 2015 it has been frozen.

Russia and Bulgaria also cooperate in the field of nuclear energy, in particular on modernization of the Kozloduy NPP.