Sistema, the Russian conglomerate, is seeking to take a significant stake in Deutsche Telekom, the German telecommunications group, in exchange for control of its telephone unit, which includes MTS, Russia's biggest mobile phone operator, according to people familiar with the issue.

Those familiar with the approach told FT Deutschland, the Financial Times' sister paper, that Sistema had approached Kai-Uwe Ricke, Deutsche Telekom's chief executive, with the proposal, which has been discussed by the German company's board.