Moscow, Russia – June 7, 2007 – “COMSTAR – United TeleSystems” JSC (“Comstar”) (LSE: CMST), the leading combined telecommunications operator in Russia and the CIS, today announced the appointment of Sergey Pridantsev as President and Chief Executive Officer with effect from June 13, 2007. Mr. Pridantsev is the former General Director of JSC CenterTelecom, a provider of fixed-line telecommunications services in the Central Federal District of Russia.

Alexander Goncharuk, President of Sistema, commented: “We are pleased to welcome Mr. Pritantsev to our management team. Over the past year the management of Comstar has implemented a number of significant changes - they have reorganized the corporate structure, integrated the companies into a combined group and made a number of large-scale acquisitions. This year, the management is focused on increasing the profitability of the company, extracting maximum synergies from the unique combination of businesses and expanding further into the regions. We are confident that the appointment Mr. Pritantsev’s who has a broad experience in the Russian telecommunications market will help us to achieve these goals”.

Sergey Pridantsev was born on August 18, 1967, in Moscow, Russia. From 2002 until recently, Mr. Pridantsev worked for CenterTelecom where he consecutively held the following positions: Adviser to General Director, Deputy General Director and Commercial Director, General Director. From 1997 to 2002 he held a number of positions at Lucent Technologies, including Head of Customer Service in Moscow and Moscow region, First Deputy General Director and Sales Director for Russia and the CIS. From January 1995 to May 1997, Mr. Pridantsev served as a technical adviser to Hewlett-Packard (Moscow). From 1994 to 1995, he worked for Astelit, a Russian fixed-line telecommunications company. Prior to that, Sergey Pridantsev served as Head of the Research Laboratory for transport and technological robotics at the Moscow Automobile and Road Institute. Mr. Pridantsev graduated from the Moscow Automobile and Road Institute (1993), Stanford Executive Institute (2000) and the Russian Academy of Public Service under the President of the Russian Federation (2004).