Che Zuobin, a section chief in the publicity department under Li's committee, said his committee and the Guangdong provincial administration of industry and commerce are now investigating the case.

"We can not force or require Esso to shut down all its gas stations unless they are found to have violated laws and regulations," Che told China Daily yesterday.

"And we are still collecting evidence and seeking suggestions from the province's associations of finished oil and relevant departments and organizations," Che said. The result of the investigation will be published in about two weeks, Che added.

Hu Yanni, a section chief from Guangdong provincial administration of industry and commerce, said the company will be fined between 50,000 yuan and 500,000 yuan if it has sold finished oil without a license, or if it has sold substandard products.

Hu urged car owners and drivers to continue to complain to administrations of industry and commerce, or the consumers' council, if they believe they have purchased any product of poor quality. But she denied her administration suggested Esso close its gas stations for self-inspection.

She refused to reveal whether Esso has been granted a license to trade finished oil.

The case has raised concerns from many government departments and the large number of car owners in the province, which borders Hong Kong and Macao special administrative regions.

Some companies and residents who have chosen Esso pumps as their designated gas stations have paid in advance.

ExxonMobil is the world's largest publicly traded international oil and gas company.

ExxonMobil markets fuels and lubricants under three names: Esso, Exxon and Mobil.