"The government is studying different options," said the official, who spoke on condition of anonymity.

One option would be to ask Exxon to suspend the Kurdistan deal, the official said, but the government is also "examining penalties that could be imposed against the company."

On October 18, Kurdistan inked a deal with ExxonMobil for it to explore six areas, according to Ashti Hawrami, Kurdistan's minister of natural resources.

But the oil ministry official said two of those areas -- Al-Qosh and Bardarash -- are actually parts of Nineveh province that Kurdistan wants to annex into its autonomous region, a move Baghdad opposes.

Baghdad regards any contracts not signed with the central government as invalid.

"The government believes that oil is the wealth of all Iraqis, and if the ministry does not have control over contracts, each province could decide to sign a contract, and this will destroy the unity of Iraq and lead to the division of the country," the official said.

The office of Hussein al-Shahristani, Iraq's deputy prime minister for energy, said Saturday "the Iraqi government will deal with any company that breaks the laws in the same way that it has in (the) past, and ExxonMobil has been notified of this."

In the past, Iraq has banned oil companies that have signed contracts in Kurdistan from taking part in tenders or contracts for other fields.

In January 2010, Iraq's oil ministry completed the deal with ExxonMobil and Anglo-Dutch giant Shell to develop production at West Qurna-1, which with reserves of about 8.5 billion barrels is the country's second-biggest field.