"Operations at Kashagan [oil field] may be suspended. We are currently conducting a probe. There is reason to believe that the operator has failed to comply with environmental laws," Nurlan Iskakov said.
"In view of non-compliance with previously-agreed obligations, we are obliged according to law to revoke permission [for the deposit's development], as its further use will cause irrevocable ecological damage. We will send relevant documents today to the energy and mineral resource ministries," he said.
Iskakov said the Central Asian country's prime minister, Karim Masimov, had directed the Ministry of Energy and Mineral Resources to look into the matter.
The premier earlier expressed dissatisfaction with the pace of work at Kashagan, and rising operation costs.
In late July, the project operator proposed to the government that the deadline for starting commercial production be shifted from the second half of 2008 to the second half of 2010, with operating costs to be increased from $57 billion to $136 billion.
Kashagan's recoverable reserves were estimated in 2000 at 13 billion barrels of oil.