A top executive of China's Baosteel Group, the parent of Baoshan Iron & Steel, is being investigated for "serious disciplinary violations," China's corruption watchdog said on Tuesday, as the country intensifies its war on deep-seated graft.

The graft watchdog, the Central Commission for Discipline Inspection, named the Baosteel official as Vice President Cui Jian but gave no further details in a short statement.

A spokesman for Baosteel, China's second largest steel maker and the world's fourth largest, said the company was aware of the investigation and was watching developments but had no further immediate comment.