In remarks on state-run radio, President Idriss Deby gave the companies part of the African country's oil production consortium that is led by Exxon Mobil a deadline of just 24 hours to start making plans to leave.

"Chad has decided that as of tomorrow (Sunday), Chevron and Petronas must leave Chad because they have refused to pay their taxes," Deby said in a message broadcast on state-run radio.

Deby said Chad, which is one of Africa's newest oil producers and is setting up a national oil company, would take over the oil fields that have been overseen by the American and Malaysian companies and account for some 60 percent of its oil production.

Sabri Syed, a spokesman for Kuala Lumpur-based Petroliam Nasional Berhad, said he could not comment on Deby's announcement.

Chevron said in a statement it had not been behind on any tax payments and had not been told it must leave Chad.

"Chevron has not received any official notification from the Republic of Chad government asking Chevron to leave the country over tax issues," the statement said. "However, Chevron has been in full compliance with all of our tax obligations.