A senior official at China Petroleum and Chemical Corp, or Sinopec Group, was taken away for questioning by anti-corruption investigators on Wednesday morning during a corporate meeting, Beijing-based Caixin reported.

Xue Wandong, general manager of Sinopec Oilfield Service Corp, a wholly owned subsidiary of Sinopec, is the first executive from the country's largest oil refiner to be placed under investigation after the country's corruption watchdog launched an inspection of Sinopec on Nov 26.

Inspectors from the Central Commission for Discipline Inspection, the country's top anti-graft watchdog, are focusing on senior figures within Sinopec who may be promoted to leadership roles, according to a Reuters report. The report also cited Xinhua News Agency as saying the inspection was expected to be completed by the end of December.

At the end of November, a series of inspections were launched into 13 State-owned enterprises and government bodies, including Sinopec, China Southern Airlines Co and China Unicom (Hong Kong).

Xue, also vice-president of the oil subsidiary, has been removed from his post, according to a notice on the company's micro blog. No further details about the investigation were given.

The post said that Sinopec has "zero tolerance" for any violations of discipline or the law. No matter who is involved, the company will follow proper procedures and will not be soft, it said.

Xue, 53, was born in Shandong province. He served as chairman of Sinopec Shengli Oil Field Dynamic Group Co from 2005 to 2008. In 2012, he became general manager of the oilfield service subsidiary. Sinopec formed it during a business restructuring.

The State-owned company is planning to list its oilfield service unit in the Hong Kong Stock Exchange in the first half of next year, according to previous media reports.

Sinopec plans to sell Sinopec Oilfield Service Corp to a Hong Kong-listed polyester maker that it controls, Sinopec Yizheng Chemical Fibre Co, according to a filing with the city's stock exchange in September.

Analysts said the investigation of Xue will affect the progress of the listing because core managers should remain in place for three years, according to regulations.

The country's energy sector has been found to be a honey pot for corrupt officials since President Xi Jinping launched a sweeping anti-graft crackdown. He warned that the problem poses a threat to the survival of the Communist Party of China.

Since 2013, several senior executives at China National Petroleum Corp, the nation's largest oil and gas firm and the parent of listed PetroChina, have been investigated for serious discipline violations.