The European Commission (EC) said the implementation of the South Stream gas pipeline project should be suspended until it is fully aligned with European legislation.
"New infrastructure investments promoted by dominant suppliers must adhere to all internal market and competition rules. In particular, the South Stream project should be suspended until full compliance with EU legislation is ensured and re-evaluated in light of the EU's energy security priorities," the Commission said in a statement on Wednesday.
The Commission's recommendation is part of its communication with the European Parliament and the Council.
South Stream, spearheaded by Gazprom, aims to diversify gas routes within the European Union and to provide stable gas supplies from Russia to central and southern Europe via Bulgaria, Serbia, Hungary and Slovenia.
According to EU energy commissioner Gunther Oettinger, however, the project seeks to supply fuel that already reaches EU, i.e. it does not represent a new energy source, the state-run radio broadcaster BNR reported.
The total value of the South Stream project is estimated at some 16 billion euro ($21.8 billion). It is planned to reach its full capacity of some 63 billion cubic metres per year by 2017.