KIEV, Feb. 13 ??“ VimpelCom, Russia??™s No. 2 cell phone company, offered to buy 100% of Kyivstar, Ukraine??™s No. 1 cell phone company, for $5 billion in the company??™s shares, the Russian cell phone company reported Monday.

The hostile takeover bid is seen as next step in a shareholder war waged between Norway's Telenor and Russia??™s Altimo, a telecommunications arm of Alfa Group.