Zhang Kunsheng was suspected of "violating discipline and is being investigated", China's foreign ministry said in a statement, Reuters reports. Details of the investigation against the diplomat are not disclosed, According to Xinhua.
The term "violating discipline" is used by Chinese authorities to describe corruption, Yonhap News said.
Zhang was the most senior of China's assistant foreign ministers and was in charge of the protocol department, Reuters said.
The fight against corruption is one of the top priorities of China's President Xi Jinping. The anti-corruption campaign has already affected a number of high-ranking officials and businessmen in the country.