Russian Energy Minster Alexander Novak said on Thursday some partners in the South Stream gas pipeline project had come under pressure from the European Union, Interfax news agency reported on Thursday.
Bulgaria suspended construction of its parts of the project this month at the behest of Brussels, pending a ruling on whether the project complies with EU law.
"The European Commission has taken a tough stance on cross-border infrastructure projects with Russian participation," the agency cited Novak as telling the World Petroleum Congress in Moscow. "Today, some of the South Stream partners are under pressure.
In particular, our Bulgarian colleagues have been threatened."