The Russian owner said it will buy back $128.9m of 2018 Eurobonds and $91.1m of 2020 Eurobonds.
A price of $0.51 has been set for the 2018 notes while the 2020 stock will be worth a cent less.
The settlement date is 14 May.
The company has said the move was considered to be "the next essential step of our liability management initiative which aimed to reduce the leverage, provide for a more optimal currency balance in the company's debt structure and maximise the shareholder value."
