The Kazakh government said in a statement Kazakh Prime Minister Karim Massimov witnessed the signing of the measure with ConocoPhillips, Mubadala Development Co. of the United Arab Emirates and the state-owned KazMunaiGas.

"The parties should now conclude a final deal on the transfer of a 49 percent stake in the subsurface management contract from KazMunaiGas to ConocoPhillips and Mubadala, which will be equally divided between the companies, by Dec. 31, 2008," the companies said in a joint release.

The news of the deal follows a weekend meeting in Astana between U.S. Secretary of State Condoleezza Rice and Kazakh Foreign Minister Marat Tazhin on energy trade.

The officials said any developments in the energy sector were based on transparent existing contracts and the move should not be seen as U.S. encroachment in the Russian sphere of influence.

"I believe that this relationship hinges on those agreements and contracts that have already been signed. It's a very transparent relationship that we have in the area of energy. And I do believe that they will be developing along those plans that we have had," Tazhin told reporters.