BEIJING, Sept. 22 (Xinhua) -- Premier Li Keqiang on Tuesday told officials to accelerate the investigation of the blasts that occurred in north China's Tianjin last month.

The authorities have achieved "preliminary identification" of how the accident occurred, damage, illegal practices, corruption and dereliction of duty, the Premier said while he was briefed on the investigation.

Li urged rigorous investigation to make clear every detail and leave no "gray area" so that every conclusion can "stand the test of time and history."

Those responsible for the accident should be severely punished according to law and discipline, no matter who is involved, Li said.

Vice premier Zhang Gaoli called for strict management of hazardous materials and prevention of accidents.

Huge explosions occurred at a warehouse in the city of Tianjin on August 12, killing 165 people and devastating the port area.