Bulgaria struck a financial agreement with Russia alongside a secret deal on the construction of South Stream, a Reformist Bloc representative said Friday.

Martin Dimitrov's comments come a day after other bloc members alleged that they had gained access to evidence of a "secret deal" with Gazprom on the South Stream project.

Dimitrov claimed in an interview with the Bulgarian National Radio that the agreement had unfavourable interest rates and added it had been signed after the start of an EU Commission infringement procedure against Sofia over the pipeline.

Though not elaborating on his sources, he referred to Thursday's announcement of the "secret" construction deal made by fellow colleague Petar Moskov.

The government is yet to confirm or deny that any deals had taken place.

Cabinet members, including Prime Minister Plamen Oresharski and Economy Minister Dragomir Stoynev are to be heard in Parliament over South Stream, after Oresharski first announced the construction of the pipeline would be frozen and Parliament Speaker Mikhail Mikov later downplayed his decision by saying the project was under way.