BEIJING, Aug. 18 -- Four former officials in north China's Shanxi Province are under investigation for abuse of power and bribery allegations.

Zhang Bao, former mayor of Changzhi city in Shanxi, is being investigated for abuse of power and bribery, according to a statement by the Supreme People's Procuratorate (SPP) released Monday.

Duan Jianguo, former head of the transport department of Shanxi provincial government, is being investigated for taking bribes.

Jia Jianming, former vice president of the state-owned Shanxi Road & Bridge Construction Group Co. Ltd, is under investigation for bribery and embezzlement.

Li Huazhong, former head of the transportation management department of Shanxi provincial government, is being investigated for bribery.

All of them have been "placed under coercive measures," the statement said.

According to China's criminal procedure law, coercive measures include summons by force, bail, residential surveillance, detention and arrest. The SPP did not specify which measures have been taken so far.