Russian authorities have searched the offices and homes of Euroset managers as part of a criminal case related to alleged smuggling.
Euroset is one of Russia's biggest mobile phone companies.
A spokeswoman at the Prosecutor-General's office declined to give details of what the case involved, other than that it was related to contraband.
Euroset has not said anything. Observers say that searches by prosecutors in Russia indicate serious problems in relations with the authorities. Often they come to nothing or are resolved without a conflict.