April 2004

30.04.2004
MTS Announces AGM Date and Recommended Amount of Dividends

Moscow, Russia — April 30, 2004 — Mobile TeleSystems OJSC (“MTS” — NYSE: MBT), the largest mobile phone operator in Russia and Ukraine, announces the calling of the annual general meeting of shareholders (AGM) and the recommended amount of dividends.

27.04.2004
The MTS Trademark Enters the Krasnoyarsk Krai

SibChallenge Joins the Unified MTS Network

20.04.2004
Mobile TeleSystems Announces Redemption of its Floating Rate Notes

Moscow, Russian Federation — April 20, 2004 — Mobile TeleSystems OJSC (“MTS” — NYSE: MBT), the largest mobile phone operator in Russia and Ukraine, announces the redemption of its $300,000,000 Floating Rate Notes on May 5, 2004.

16.04.2004
MTS’ subscriber base exceeds 20 million

MTS’ consolidated subscriber base in Russia, Belarus and Ukraine reached 20.28 million as at April 16, 2004.

16.04.2004
MTS Increases Ownership in its Khabarovsk Subsidiary

Moscow, Russian Federation — April 16, 2004 — Mobile TeleSystems OJSC (“MTS” — NYSE: MBT), the largest mobile phone operator in Russia and Ukraine, has acquired an additional 40% stake in Far East Cellular Systems-900 CJSC (“FECS-900”), increasing its ownership in the company to 100%.

13.04.2004
MTS Increases Ownership in its Omsk Subsidiary

Moscow, Russian Federation — April 13, 2004 — Mobile TeleSystems OJSC (“MTS” — NYSE: MBT), the largest mobile phone operator in Russia and Ukraine, has acquired an additional 7.5% of Mobilnye Sistemy Svyazi OJSC (“MSS”), increasing its ownership in the company to 91%.

08.04.2004
07.04.2004
May Holidays in Sochi! Call 082.

The holiday season is approaching and MTS would like to offer you a suggestion on how to spend it.

Contact investor relations:

+ 7 495 223 20 25 ir@mts.ru

MTS Investor Relations
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