Two senior executives at companies in the China Resources group were detained immediately after the state-run conglomerate's former chairman, Song Lin, was placed under investigation for corruption, sources familiar with the matter have revealed.
China Resources Capital Holdings chief executive Wu Ding, 49, was taken away hours after the Communist Party's anti-graft agency said last Thursday that it was probing Song, two sources said on condition of anonymity.
Wang Hongkun, the executive director of China Resources Land, was detained the same day, different sources said. The detentions of Wu and Wang showed the investigation into China Resources was widening, the sources added.
The anti-graft agency said Song was "suspected of grave violations of discipline and law" - a form of words it often uses to describe corruption.
A company statement released by China Resources Land on Tuesday said Wang, 46, had resigned because of ill health. A company spokeswoman said she was not aware of the "rumours" about his detention.
One of the sources said: "Wu is a close friend of Song and has connections with some senior officials."
Meanwhile, Li Fuzuo, the chairman of China Resources Pharmaceutical Group, was also on leave, the company's spokeswoman said.
"He is still our chairman. He is still in the company, although recently he had something on at home and asked for leave to deal with that," she added.
One of the sources said Li was in the US with his family.
All three senior executives are veteran staff at China Resources, which controls five listed companies in Hong Kong, spanning natural resources to real estate.
Song rose through the conglomerate's ranks to become chairman in 2008.
Before facing the probe, at least two reporters accused Song of personally profiting from assets China Resources bought in Shanxi province.
China Resources announced on Wednesday that Fu Yuning, former head of the state-owned ports-to-financial services conglomerate China Merchants Group, would replace Song as chairman. The government's anti-corruption campaign has partly focused on state-owned enterprises, which have made massive profits from their monopolies and preferential government policies.
Jiang Jiemin, the former chairman of the state-owned oil giant China National Petroleum Corp, was placed under investigation for alleged corruption last year.
Additional reporting by Sophie Yu and Peggy Sito