**Exhibit 4.25.1**

**AdditionalAgreement No. 1**

**To Agreementbetween OAO Rostelecom and OAO Uralsvyazinform No. 751-05-23,dated December 28, 2005**
| Moscow |   | January 01, 2006 |
|--------|--------|-----------------------|

 

Rostelecom, Open Joint-Stock Company for Long-Distance and InternationalTelecommunications, hereinafter, “Rostelecom”, represented by OAO RostelecomGeneral Director Dmitry Yevgenievich Yerokhin, authorized to act by Charter, onthe one part, and “Uralsvyazinform”, an Open Joint-Stock Company, hereinafterreferred to as the “Operator”, represented by General Director AnatolyYakovlevich Ufimkin, authorized to act by Charter, on the other parthereinafter collectively referred to as the “Parties”, and severally, as “Party”,have entered into this Additional Agreement (hereinafter, “the Agreement”) onthe incorporation of the below-listed amendments in the Contract on NetworkConnection (hereinafter, “the Contract”), as follows:

1.                             Clause1.6. of the Contract shall read as follows:

«1.6.“Users” shall mean persons including subscribers who orders and/or usestelecommunication services through the Operator, or through thetelecommunications operator whose telecommunication network is connected to theOperator’s network at the local or zone level, and who is not the AssociatedOperator, provided that settlements with the mentioned persons fortelecommunication services rendered by Rostelecom shall be made by the Operatorpursuant terms and conditions of this Contract. The list of telecommunicationsoperators whose telecommunication network is connected to the Operator’snetwork at the local or zone level, who is not the Associated Operator,settlements with whom for telecommunication services rendered by Rostelecomshall be made by the Operator pursuant terms and conditions of this Contract,will be provided in a separate Additional Agreement which shall be entered intoby the Parties after or concurrently with this Contract’s coming into force”».

2.                             Clause1.4. of the Contract shall be amended as follows:

«1.4.“Accrued income” means payments to the Operator by the Users for the Servicesrendered in the corresponding month».

3.                             Clause1.7. of the Contract shall be amended as follows:

«1.7. “Revenue earned” means  the income actually received by the Operatorfrom the Users in the corresponding month on account of payment for theTelecommunication Services».

4.                             Clause1.8. of the Contract shall be amended as follows:

« 1.8. “Billing period” means a calendar monthfollowing the Accounting period».

5.                             Article 1of the Contract shall be added by Paragraph 1.13. as follows:

«1.13. “Billing period”means a calendar month during which Telecommunication Services were rendered tothe Users».

6.                             Paragraph3.3.10 of the Contract shall be added by the following provision: “Make secondcopies of invoices”.

7.                             InParagraph 3.3.11 of the Contract, the words “second copies of invoices” shallbe inserted before the words “billing data”.

8.                             InParagraph 3.3.4 the words “within 10 days following the invoice” shall besubstituted by the words “within 15 days following the invoice”.

9.                             InParagraph 4.1.2. of the Contract, the sentence “The amount of payment, thesettlement procedure between the Parties for the Services rendered by theOperator to Rostelecom, shall be provided for by Appendix 2 to the Contract”shall be substituted by the sentence “The amount of payment, the settlementprocedure between the Parties for the Services rendered by the Operator toRostelecom, shall be provided for by Appendix 7 to the Contract”.

10.                       Appendix 3 shall be amended in version 2:

11.                       Appendix 4 shall be amended in version 2:

12.                       Appendix 5 shall be amended in version 2:

13.                       Appendix 7 of the Agreement****shall be amended as follows:

----

**Appendix No. 7**

**Dated 01 January, 2006**

**PARTIES MUTUALSETTLEMENT PROCEDURE**

1.               The monetaryobligations of the Operator to Rostelecom (para. 4.1.1 of the Agreement).

1.1.           Within the termbefore the 25th day of the Billing period the Operator must transfer toRostelecom one hundred per cent (100%) of the Accrued income for the monthpreceding the Billing period for the Telecommunication Services rendered duringall periods preceding the Billing period, in accordance with the Operator’sReport.

1.2.           Irrespective ofany provision of para. 1.1 of this Appendix 7 contradicting the understated,before the 25th day of the Billing period the Operator must transfer toRostelecom, irrespective of the amount of payment received in the monthpreceding the Billing period, no less than the Minimal payment in the amount of34 % of the Accrued income for the Services rendered during the month precedingthe Billing period (para. 4.1.1 of the Agreement).

1.3.           Rostelecompresents to the Operator the invoice for the payment of the Revenue earned, forthe amount determined with the consideration of para. and 1.2. hereof, beforethe 20th day of the Billing period.

2.               The monetaryobligations of Rostelecom to the Operator (para. 4.1.2. of the Agreement).

2.1.           Rostelecom isobliged to pay to the Operator the consideration for the services rendered bythe Operator to Rostelecom in accordance with para. 2.2 and theremuneration for the fulfillment by the Operator of the commission specified inpara. 2.1. of Section 2 of this Agreement, within the terms and inthe amount stated below. The total sum of the monetary obligations ofRostelecom for the services rendered to Rostelecom by the Operator inaccordance with para. 2.2 and the remuneration for the commissionperformed by the Operator, specified in para. 2.1. of Section 2 ofthe Agreement, in every corresponding period is calculated on the basis of theAcceptance Acts signed by the Parties for the corresponding periods.

2.2.           Within the termbefore the 25th day of the Billing period Rostelecom is obliged to transfer tothe Operator the payment in the amount Y, which equals the sum of the paymentsnot transferred by Rostelecom by the above indicated date of payment for theservices under the Agreement rendered Rostelecom by the Operator during all theperiods preceding the corresponding Billing period, the cost of which has beenestimated in accordance with Appendix 2 to the Agreement. At that, the maximumamount of payment Y, due to transfer in every Billing period equals M, thevalue calculated for every Billing period by the following formula:

M= Areceived – Amin. where

M—isthe maximal value of payment Y due to payment to the Operator byRostelecom  in the corresponding Billingperiod.

Areceived—is the Revenue earned in the month preceding theBilling period, in accordance with the Operator’s Report, for the TelecommunicationServices rendered by Rostelecom to the Users during all periods preceding theBilling period.

A min—the amount ofthe Minimal payment, in accordance with para. 1.2. hereof.

Thecalculated payment Y is included into the cost of the services rendered by theOperator to Rostelecom under this Agreement for all periods of its validity, inthe part in which these services were not paid for by the moment of thecalculation of the payment. The Parties agree that in the first place thepayments account for the services rendered during the earlier periods.

2.3.           Rostelecomtransfers to the Operator the payments, in accordance with para. 2.2.hereof, until the amount of all payments transferred by Rostelecom inaccordance with this para. 2 equals the total cost of the servicesrendered by the Operator to Rostelecom under this Agreement.

----

2.4.           The Operatorpresents to Rostelecom the invoices for the payments specified inpara. 2.2. hereof, for the sums calculated in accordance with thementioned paragraph, before the  20th dayof the month in which the corresponding payment is due to be performed.

3.               With the purposeof the termination (full or partial) its obligations indicated in paras 1 and 2of this Appendix  and the termination ofthe obligations of Rostelecom to the Operator under the Contract on networkconnection __________________________ in the version of ________________________(“Contract on Connection”), the Parties to have monthly setting off thecounter-claims by signing the Acts of offsetting counter-claims on the dayswhen such obligations of the Parties shall be fulfilled under this Agreementand the Contract on Connection.

14.        Appendix8 shall be amended in version 2:

Add Clause 8 to Appendix 9 in the following version:

«8. Provision of information regarding users’ accountsreceivable in order to create a reserve on doubtful debts for taxationpurposes.»

The Operator shall on a monthly basis, by the 15th dayof the month following the month of the end of the quarter, provide Rostelecomwith the electronic report on the indebtedness for the Services of Rostelecomas of the last date of the quarter, by form 9 (in Excel).

15.        ThisAgreement is an inseparable part of the Contract.

16.        Allterms used in this Agreement have a meaning, fixed for them in the Contract.

17.        Allthe rest, not indicated in this Agreement, is subject to the provisions of theContract.

18.        Theagreement is issued in the Russian language in two copies, one for  each Party.

19.        ThisAgreement shall come into force from the date hereof. The Parties herebyestablish that terms and conditions of the Agreement entered into thereby shallapply to their relations arisen from the date of the Contract onTelecommunications Network Connection dated January 01, 2006.

20.        Detailsand Signatures of the Parties
| OAO Rostelecom:                |   | OAO Uralsvyazinform:                |
|--------------------------------|--------|-------------------------------------|
|                           |   |                                |
| Legal address: 127091, Moscow, |   | Legal address: 620014               |
| Delegatskaya st., 5            |   | Yekaterinburg, Moskovskaya  st., 11 |
|                           |   |                                |
| General Director               |   | General Director                    |
|                           |   |                                |
|                           |   |                                |
| /signed/ D.Ye. Yerokhin        |   | /signed/ A. Ya. Ufimkin             |
|                           |   |                                |
| January 01, 2006          |   | January 01, 2006               |
|                           |   |                                |
| Seal here                      |   | Seal here                           |

 

----