At least 17 people were killed and around 400 injured in two massive explosions in the northeastern Chinese port city of Tianjin on Wednesday.

Video posted on Youtube showed fire shooting into the night sky.

Chinese media sources said the blasts came from a shipment of explosives but those reports are unconfirmed.

The first explosion happened at around 1130pm local time and was reportedly felt several miles away. The second blast came around 30 seconds later.

Hospitals were reported to be overwhelmed with casualties with the official Xinhua news agency saying around 400 people were injured.

President Xi Jinping demanded that the authorities make “every effort to rescue and treat the injured, and ensure the safety of people and their property.”

The military have been brought in to help control the situation.

Evidence of the strength of the blasts could clearly be measured by the extent of the damage to hundreds of buildings surrounding the industrial complex.