Russian gas giant Gazprom may finance the Bulgarian part of the South Stream gas pipeline, intended to carry natural gas to Europe, in lieu of future payments for gas transit, a source close to the project said late on Friday.

"Gazprom may pay for [the Russian] part as well as for the Bulgarian part and then cover its losses by transit payments," the source told reporters.

This week Bulgarian Economy, Energy and Tourism Minister Delyan Dobrev has said that Sofia might not sign an agreement for South Stream construction till November 15 as Russia made new demands to the financial model of the project before agreeing to provide an 11.1 percent discount on gas for this year.

The source said that difficulties arose due to the fact that Bulgaria had not enough funds to finance its part of the project.

The final investment decision on the project is scheduled to be made in November 2012.

The South Stream pipeline is intended to transport up to 63 billion cubic meters of natural gas to central and southern Europe, diversifying Russian gas routes away from transit countries such as Ukraine.

Construction will start in December 2012. Russia plans to start using the pipeline in 2015.

The pipeline's core shareholders include Gazprom with 50 percent, Italy's Eni with 20 percent and Germany’s Wintershall Holding and France's EdF with 15 percent each.