April 17, 2003, Moscow, Russia. SISTEMA JSFC announces the intention to realize its option for buying a 10 % stake in the Russian company Mobile TeleSystems JSC (MTS - NYSE: MBT) being owned at present by T-Mobile International AG.

Under the purchase option that was given to SISTEMA JSFC by T-Mobile International AG (T-Mobile), a subsidiary of Deutsche Telekom, in accordance with the option agreement of March 12, 2003 SISTEMA JSFC has the right to acquire a 10% stake in MTS, which is now either directly or indirectly owned by T-Mobile. SISTEMA JSFC reports that it has made the decision to use the purchase option right and has appropriately notified T-Mobile. At present, SISTEMA JSFC owns a 40.4% stake in MTS. Executing this option will make the stake of SISTEMA JSFC in MTS the controlling one and permit SISTEMA JSFC to consolidate MTS’ financial results in its accounting. The given purchase corresponds to the strategy of SISTEMA JSFC aimed at investing and developing the main directions of its activity.

In this connection Vladimir Evtushenkov, the chairman of the board of directors, said: "MTS is one of our best and favorite projects and we are satisfied with an opportunity to increase our stake in MTS. The execution of this option permits us to continue our successful partnership with Deutsche Telekom and to implement our plans to make MTS a leader of the mobile phone communication service in Eastern Europe".

The Joint Stock Financial Corporation SISTEMA (SISTEMA JSFC) is of the largest diversified holdings in Russia. SISTEMA JSFC was founded in 1993. At present, it owns and actively manages various enterprises in the following fields of the country’s economy: telecommunications (MTS, MGTS, MTU-Inform, Telmos, Golden Line, Comstar, etc), electronics (NIIME & plant MIKRON as well as a number of enterprises of microelectronics), insurance (ROSNO), finances and securities (MBRD JSB), real estate and construction (SISTEMA-HALS), tourism (Intourist), retail (Detsky Mir Trading House) and others.

Mobile TeleSystems JSC (MTS) is the largest operator of the mobile phone communication in Russia, Central and Eastern Europe. Together with its subsidiaries the company services over 9.7 million subscribers. MTS and its subsidiaries are licensed to provide GSM standard services in 58 regions of Russia as well as in Belarus and Ukraine with a total population of approximately 169.2 million people. At present, MTS is servicing subscribers on the territory of 48 subjects of the Russian Federation incorporated in the Central (including Moscow and Moscow region), North-Western (including St. Petersburg and Leningradskaya region), Southern, Pryvolzhsky, Uralsky, Siberian and the Far Eastern Federal Districts of the Russian Federation. Since June 2000 the company’s stock has been listed on the New York Stock Exchange as ADR with the ticker symbol MBT. Additional information on MTS can be found on the company’s website at www.mtsgsm.com

This document is not an offer for sale of securities in the United States. The company’s securities can be offered for sale or be sold in the United States, if only they are registered with the U.S. Securities and Exchange Commission or under exemptions from the registration rules. Any public offer for sale of the company’s securities in the United States should be implemented through issuing the emission data sheet, which can be obtained from the company and which should contain a detailed information on the company and the management bodies, including its financial accounting. Not to be released in the U.S.