Local government officials in China repeatedly warned a car parts factory that was rocked by a deadly blast over the weekend that high levels of dust could spark an explosion, the South China Morning Post newspaper reported Monday.

The blast at the Kunshan Zhongrong Metal Products Co. Ltd. factory in the city of Kunshan killed at least 71 people on Saturday and injured more than 180.

A preliminary investigation suggested it was triggered when a flame was lit in a dust-filled room, the local government said at a Saturday news conference, describing the incident as a serious safety breach.

The company had ignored prior warnings about dust, an unidentified official at the Kunshan Administration of Work Safety told the newspaper.

Neither Kunshan officials nor executives from Kunshan Zhongrong could be reached for comment.

Based about an hour's drive from Shanghai, Kunshan Zhongrong polishes wheel hubs for automakers including General Motors Co. The blast is China's worst industrial accident in a year.

The official Xinhua News Agency said two company representatives had been taken into police custody and that President Xi Jinping had demanded a full inquiry into what happened and punishment for those responsible.