Russian Stroytransgaz consortium will build the Bulgarian stretch of the South Stream gas pipeline, it was revealed.

A major shareholder (63%) in Stroytransgaz is Volga Group, owned by Gennady Timchenko, who was placed on the US's sanctions list against Russia in mid-March. He is believed to be the 6th richest man in Russia, according to Forbes, and with close ties to President Vladimir Putin.

Bulgaria's Capital daily reported earlier this year that Stroytransgaz has expressed interest in building the pipeline, but official confirmation came on Tuesday by Vladimir Inkov, executive director of South Stream Bulgaria.

Stroytransgaz's main Bulgarian partner in the project will be Gazproekt Yug (South), which includes several major construction companies.

The tender for South Stream's construction in Bulgaria opened in December 2013. A total of 11 companies from Austria, Japan, Belgium, Germany, Italy, India, Russia, Switzerland, and Bulgaria took part.

Despite the European Commission's recommendations for renegotiation of the South Stream project, Gazprom CEO Alexey Miller confirmed last month that the building of the pipeline's ground stretch in Bulgaria and Serbia will begin in July.

Bulgaria also faces pilot procedures in the European Commission over controversial amendments to the status of South Stream, which are allegedly not in line with EU law.