A court marshal accompanied by about 15 armed men in uniform visited Telenor 's Moscow office Friday to hand over a request for information, the Norwegian group said.
"We consider it an effort to pressure Telenor during the continued dispute between VimpelCom shareholders," a spokeswoman said, adding that such requests are typically sent by mail.
The information requested was regarding whether Telenor will exercise an option to buy an additional 3.5 percent stake in VimpelCom from Egyptian tycoon Naguib Sawiris ' holding company Weather.
The Federal Anti-Monopoly Service brought a lawsuit against Telenor earlier this year in which it alleged that a purchase of VimpelCom shares that Telenor made in February violated the Strategic Investment Act.
In February, Telenor raised its voting stake in VimpelCom to 36.3 percent from 25 percent after buying shares from Weather. Telenor increased its stake further, to 39.51 percent, in April.
RIA -Novosti reported that the head of the monopoly watchdog, Igor Artemyev , said Wednesday that a resolution was needed by Oct. 1, the expiration date of an option under which Telenor may buy the extra shares.
The marshal's office was not available to comment.