Russia's Federal Antimonopoly Service, or FAS, is preparing a lawsuit against Norwegian telecommunications operator Telenor ASA (TEL.OS), which has increased its stake in VimpelCom Ltd. (VIP) to 39.51% from 25.01% since the beginning of the year, Interfax reported Monday citing FAS.

The regulator says that Telenor has breached a law regulating foreign investments in companies the state deems strategically important.

Should the lawsuit be accepted by the court, and should the ruling go against Telenor, the deal with the Norwegian company could be annulled, according to the report.

Agency website: www.interfax.ru

-By Moscow Bureau, Dow Jones Newswires; +7 495 974 8026