Xu Yongsheng, deputy administrator of the National Energy Administration (NEA), has been "taken away" by authorities as part of a sweeping investigation into corruption in the energy sector, according to a newspaper report.
Xu is the highest-ranking energy official to be detained since Liu Tienan, former head of the NEA and deputy chief of the powerful National Development and Reform Commission (NDRC), was held last year.
A number of high-ranking energy officials have been caught in the anti-graft probe of the energy sector - one arm of a wide-ranging anti-corruption effort spearheaded by China's leaders.
Authorities detained Xu along with another official with the NEA's new energy department, whom the report, in the 21st Century Business Herald, a bi-weekly mainland newspaper, did not name.
He was appointed to his current post in 2012.
The charges against Xu are not known, but investigators found more than 100 million yuan (HK$125 million) in cash at the home of Wei Pengyuan, one of his subordinates.
Wei, deputy director of the NEA's coal department, was detained last month, according to Caixin, a mainland news service. Authorities found Wei had bought several apartments and used one of them to store the huge pile of cash. Investigators had to borrow bank cash-counting machines after several of their own crashed under the excessive workload.
The cash weighed more than 1.15 tonnes. If stacked in 100-yuan notes the resulting pile would reach 100 metres high, according to estimates.
Hao Weiping, director of the NEA's nuclear energy department, was also detained last month.
With the anti-graft operation probing deeper into government and state-owned enterprises, more heads have rolled. The party's graft watchdog announced on Friday night that Wang Shuaiting , chairman of China Travel Service (Hong Kong) and a former head of China Resources Power, had been detained. Meanwhile, Bo Qiliang , overseas operations chief of the state oil giant PetroChina, was also placed under investigation.
CTS vice-chairman Yiu Si Wing told the Sunday Morning Post yesterday that he was surprised by Wang's detention and was unclear as to why he was being investigated.
"I'm just like you. I only saw the notice last night," Yiu said.
"I don't think it will affect the business because it seems to have to do with [Wang's time at] China Resources Enterprise and not us."
China Resources group chairman Song Lin was sacked last month and is the focus of an internal Communist Party inquiry, the South China Morning Post reported on April 26.
Wang served as chairman of China Resources Power from August 2003 to July 2010.
Yiu said CTS had not yet announced who would serve as interim chairman.