UPDATE 1-Kazakhtelecom to sell 51 pct stake in GSM firm

* To sell stake in Mobile Telecom Service

* Says sale part of resource optimisation plan

(Adds details on sale timeframe, background in acquisition)

ALMATY, June 29 (Reuters) - Kazakh state-controlled fixed line operator Kazakhtelecom KZTK.KZ plans to sell its 51 percent stake in small GSM provider Mobile Telecom Service, it said on Monday.

It said the decision to sell the stake was made "in line with the strategy and programme of asset restructuring... aimed at strengthening the core business and optimising the use of resources."

Kazakhtelecom said it would accept applications from potential investors until July 17, and August 31 would be the deadline for "binding offers". The company did not say how much it plans to raise from the sale.

The chief executive of Russia's largest mobile operator, Mobile TeleSystems (MBT.N), said an interview last month he was interested in a Kazakh acquisition [ID:nL8582813].

Kazakhtelecom said in a statement it has hired RBS Corporate Finance Limited to advise it on the sale of the stake in Mobile Telecom Service, which has 920,000 subscribers .

The country's two main GSM operators, GSM Kazakhstan and Kar-Tel, a subsidiary of Russia's Vimpelcom (VIP.N), have 7.5 million and 6 million subscribers, respectively. (Writing by Olzhas Auyezov; Editing by Hans Peters)