July 2003

Mobile TeleSystems (MTS) Launched $300 Million Bond

Moscow, Russian Federation — July 28, 2003 — On July 25, 2003 Mobile TeleSystems OJSC (“MTS” — NYSE:MBT) launched an issue of US$300 million 1-year unsecured 144A/Regulation S Floating Rate Notes in the international debt capital markets.

MTS Increases its Ownership in UMC to 100%

Moscow, Russian Federation — July 27, 2003 — Mobile TeleSystems OJSC (“MTS” — NYSE: MBT), announces that a shareholders meeting of Ukrainian Mobile Communications (UMC) approved the transfer of a 16.3% stake in UMC to MTS. Completion of the transfer and MTS’ ownership of this stake is subject to the registration of this transfer with Ukrainian registration authorities.

Mobile TeleSystems Announcement

Moscow, Russian Federation — July 23, 2003 — Mobile TeleSystems OJSC (“MTS” — NYSE:MBT) informs that the board of directors of Moscow City Telephone Network (MGTS) has nominated MTS President Mikhail Smirnov, as the new general director of MGTS. Mr Smirnov has accepted the offer, which is subject to confirmation by MGTS shareholders on August 15, 2003, to head MGTS, one of the largest fixed line operators in Russia.

MTS launches its operations in Khanty-Mansiisk AO: new low tariffs

From July 22, 2003 MTS low tariffs for intranet roaming apply in Khanty-Mansiisk AO. Thus, MTS low roaming tariffs apply now in 55 Russia's regions, in Belarus and in Ukraine.

Khanty-Mansiisk AO: MTS operates now in 50 Russia's regions!

MTS announces the launch of its operations in Khanty-Mansiisk AO and opening of sales and customer care offices in Surgut.

MTS Signs Agreement to Acquire Sibchallenge, a Leading Operator in the Krasnoyarsk Region

Moscow, Russian Federation — July 23, 2003 — Mobile TeleSystems OJSC (“MTS” — NYSE: MBT), has signed an agreement to acquire 100% of Sibchallenge, a GSM operator in the Krasnoyarsk region of Russia.

People with limited hearing are offered MTS special managers

MTS announces the launch of the special program on providing services to users with limited hearing and speech. Managers who have a command of the sign language for deaf persons start operating at some MTS offices in Moscow.

Mobile TeleSystems Announces New Appointments

Moscow, Russian Federation, 4 July 2003 — Mobile TeleSystems OJSC (“MTS” — NYSE: MBT), the largest mobile phone operator in Russia and Central and Eastern Europe in terms of subscribers, has appointed Nikolay Tsekhomsky as Vice President for Finance (Chief Financial Officer).

Contact investor relations:

+ 7 495 223 20 25 ir@mts.ru

MTS Investor Relations
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