Russia's OAO Gazprom (GAZP.RS) and OAO SUEK must sell some of their regional assets before a planned merger between the pair can be approved, the head of the Federal Antimonopoly Service Igor Artemiev said Wednesday, the Interfax news agency reported.

Russia's OAO Gazprom (GAZP.RS) and OAO SUEK must sell some of their regional assets before a planned merger between the pair can be approved, the head of the Federal Antimonopoly Service Igor Artemiev said Wednesday, the Interfax news agency reported.

The comments follow an agreement Tuesday between the two companies over a planned merger of their energy and coal assets that would see them together control a large chunk of Russia's electricity market.

"We...ask Gazprom and SUEK to sell part of their assets in order to balance competition in all the regional markets," Artemiev said. He added that the merger nevertheless contains certain pluses, but didn't elaborate.