Moscow, Russian Federation – Mobile TeleSystems OJSC (“MTS” – NYSE: MBT), the leading telecommunications provider in Russia and the CIS, announces that on January 21, 2011 the Company sent a letter to the Government of Turkmenistan inviting it to resolve the dispute over the suspension of MTS’ operations in the country and to remove impediments to the Company’s business activities in Turkmenistan.

In the letter sent to the Government of Turkmenistan, MTS warns that as a result of actions undertaken by the Turkmen authorities, their agents and/or third parties acting on behalf of the Government of Turkmenistan and/or on its instructions, MTS has suffered and continues to suffer significant losses.

The aforementioned letter is a formal request to resolve the dispute through negotiations within the framework of the procedure for settlement of investment disputes provided for by the Bilateral Investment Treaty signed by the Russian Federation and Turkmenistan. Should the dispute not be resolved amicably, MTS reserves the right to commence proceedings against Turkmenistan in the International Centre for Settlement of Investment Disputes (“ICSID”), which is part of the World Bank Group.

As was previously announced, the Company had suspended its operations in Turkmenistan in accordance with the notice from the Ministry of Communications of Turkmenistan received by MTS on December 15, 2010. The notice informed the Company of a decision to suspend telecommunications licenses held by Barash Communications Technologies, Inc. (“BCTI”), MTS’ wholly-owned US subsidiary running operations in Turkmenistan, for a period of one month starting from December 21, 2010. Given that the actions of the Turkmen authorities prevent the Company from providing services to its customers, the operations will remain suspended until removal of certain impediments to run the Company’s business in Turkmenistan through negotiation with the Turkmen authorities.

The Company shall vigorously defend its legal rights and investment interests.