* Says in talks with all shareholders

* Karachaganak is Kazakhstan's main gas producer

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ASTANA, Dec 29  - Kazakhstan is in talks with a group of foreign companies led by BG (BG.L) and Eni (ENI.MI) to buy a stake in their Kazakh gas condensate project Karachaganak, Prime Minister Karim Masimov said on Tuesday.

Talks are going on between the Energy Ministry, (state energy firm) KazMunaiGas and all project participants on this issue, Masimov told reporters.

He declined to provide details.

Apart from BG and Eni, Karachaganak shareholders include Russia's LUKOIL (LKOH.MM) and U.S. firm Chevon (CVX.N).

The field, located in Western Kazakhstan, holds 1.2 billion tonnes of oil and gas condensate and 1.35 trillion cubic metres of natural gas.

Karachaganak operators sued Kazakhstan this year to recover over $1 billion in export duties and other payments but suspended legal proceedings in October. (Reporting by Raushan Nurshayeva; Writing by Olzhas Auyezov)