Moscow, Russian Federation — April 18, 2006 — Mobile TeleSystems OJSC (“MTS” — NYSE: MBT), the largest mobile phone operator in Russia and the CIS, announces the latest developments concerning Bitel.

During the last press conference, MTS’ management indicated that it would provide an update on the latest legal developments concerning Bitel. In light of this, please find the following information:

As announced in December 2005, MTS acquired a 51% stake in Tarino Limited. Tarino Limited was at that time the indirect owner, through its 100% owned subsidiaries, of Bitel LLC, a Kyrgyz company holding a GSM 900/1800 license for the entire territory of Kyrgyzstan. After a decision of the Kyrgyz Supreme Court on December 15, 2005, Bitel’s offices were seized and currently MTS has no operational control over Bitel. 

On March 3, 2006, Mr. Glenn Harrigan, the court-appointed receiver of Fellowes International Holdings Limited (“Fellowes”), a British Virgin Islands corporation, filed a claim with the Supreme Court of the Kyrgyz Republic seeking a review and reversal of the Supreme Court’s ruling of December 15, 2005 in favor of Fellowes upholding a first instance court’s decision, whereby the shares in Bitel were transferred to Fellowes. Mr. Harrigan seeks a reversal of the Kyrgyz Supreme Court ruling on the grounds that the persons who had represented Fellowes before the Kyrgyz Supreme Court were not authorized to represent Fellowes. Fellowes is not affiliated with MTS. 

MTS will continue to vigorously assert its rights with respect to Bitel in the courts of Kyrgyzstan. Currently, MTS is working with Tarino Limited’s 49% shareholder, who has a purported right to put its shares of Tarino Limited to MTS for $170 million in November-December of 2006, to recover ownership and operational control of Bitel. Also, there is on-going litigation in the British Virgin Islands and arbitration in the United Kingdom related to Tarino Limited’s ownership of Bitel. These matters are likely to be subject of continued and/or new legal disputes and litigation, including concerning the agreements with respect to Tarino Limited. It is not possible at this time to predict the outcome or resolution of any such disputes or litigation; however, MTS believes that its position is meritorious.