The mainland's anti-corruption agency is investigating the chairman of China Resources Holdings after domestic media repeated accusations that a unit of the state-owned company deliberately overpaid for coal assets. Song Lin, whose company is the parent of five Hong Kong-listed units, was being probed for "suspected disciplinary violations", the Chinese Communist Party's Central Commission for Discipline Inspection said in a statement on its website using language that signalled a corruption probe. His company controls China Resources Power Holdings, which was accused last year of paying too much for three coal mines in Shanxi province in 2010. The probe is a signal that the Communist Party is intensifying a campaign to root out the corruption that President Xi Jinping has said threatens its six-decade hold on power. Party leaders have promised to target both "tigers and flies", or cadres up and down the power ladder, over graft. A journalist at a newspaper owned by Xinhua said on Wednesday that he had reported Song to the anti-graft watchdog, according to China Daily . The accusations were a total fabrication, Song said in a statement on China Resources' website. The three coal mines were high-quality assets and worth the investment, Wang Yujun , president of China Resources Power, said in August. Song is not the first to be investigated following allegations of wrongdoing in state media. The Communist Party fired a vice chairman of the economic planning agency in May last year after a journalist posted allegations that he had improper business dealings. More than 180,000 party officials were punished for corruption and abuse of power last year, according to the Central Commission for Discipline Inspection. China Resources would fully co-operate with a probe of its chairman, the company said yesterday.