The crackdown on corruption in the energy sector deepened as several senior government officials and company heads have been placed under investigation.

The deputy director of the National Energy Administration, Xu Yongsheng, is being investigated by the top discipline inspection body, 21st Century Business Herald reported on Saturday.

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The report, citing an internal document, said that Xu and another official from the new energy department of the NEA were led away by inspectors.

An official from the NEA, who refused to be named, said that Wang Jun, deputy head of new energy department under the NEA, was the other official under investigation.

The NEA was established in 2008 to reform the development of China's energy industries.

Xu, 48, from Shandong province, had been the head of the electricity department under the NEA in 2008 and was appointed deputy head in December 2012.

On Saturday, his name was still listed on the NEA website as deputy head of the administration.

In another recent case, law enforcement officers found almost 100 million yuan ($16 million) in cash in the home of Wei Pengyuan, a deputy director of the NEA's coal department, caixin.com reported on Thursday.

Officers found the money when they took Wei into custody at his home. They borrowed 16 currency-counting machines from a Beijing bank to tally the cash, the report said.

Wei is still under investigation.

Hao Weiping, director of the electricity department under the NEA, was also investigated early last month. He was promoted to his post in 2008.

Wu Zhouchun, former general manager of Guangdong Provincial Grid, was also reported as under investigation.

It was unclear whether the cases are related to that of Liu Tienan, former head of the National Development and Reform Commission and former head of the NEA, who was investigated in 2013.

Liu's case was first disclosed online by a journalist for his suspected financial violations.

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