Zhang Zhijiang, deputy general manager of the network unit of China Unicom

A senior executive with China Unicom is under investigation, the discipline watchdog of the State-owned Assets Supervision and Administration Commission said on Monday.

More State-run business executives are expected to be probed as the latest round of discipline inspection targets the enterprises, experts said.

Zhang Zhijiang, deputy general manager of the network unit of China Unicom, is being investigated on suspicion of discipline violations, according to a report published on the website of the Central Commission for Discipline Inspection, China's top disciplinary watchdog.

Zhang was also responsible for network building at China Unicom.

Previous media reports showed that Zhang is a top mobile telecommunication expert, and was in charge of 3G-technology research at China Unicom.

No details of the investigation were released. China Unicom confirmed the investigation of Zhang on its Sina micro blog account on Monday.

The post said that China Unicom has zero tolerance for any behavior that breaks the law or the rules.

The investigation of Zhang was announced 18 days after a discipline inspection team was sent to China Unicom at the end of November. The team is scheduled to stay there until Dec 26.

Zhu Lijia, a professor and specialist in anti-corruption studies at the Chinese Academy of Governance, said discipline inspection is now focusing on State-owned enterprises.

"Many of the State-owned enterprises are more or less in businesses that have monopoly concerns. Take the telecom sector in China as an example. The whole industry is controlled by three SOEs and is not fully open to competition in the market," said Zhu.

He added that these enterprises are likely to have corruption because their development is influenced more by power than by the market.

A large number of senior SOE managers－many of them from the oil and gas industry－h(huán)ave been investigated on corruption allegations since 2013.

Qiang Weidong, secretary of the disciplinary commission with the State-owned Assets Supervision and Administration Commission of the State Council, said earlier in December that it is still challenging to fight corruption in SOEs.

"Despite the ongoing anti-corruption campaign, many of the SOEs still take the risk of breaking the rules," he said.

Qiang said that construction, procurement and marketing are the areas most likely to have corruption.