Police had not released any information regarding casualties or the cause of a fire at a chemical plant in Tianjin Monday.

Explosions were heard before the fire broke out in the Tianjin Talent Chemistry Company at a hi-tech industrial park in the city's Beichen district on Monday, witnesses were quoted by people.com.cn as saying.

The China Network Television reported that over 20 fire trucks were at site as firefighters tried to prevent further explosions by cooling down six chemical storage tanks.

An employee of a massage spa close to the plant surnamed Yang told the Global Times Monday that the fire broke out around lunchtime.

"I heard explosions, then saw large clouds of smoke and fire. There were police officers and firefighters everywhere. The officers evacuated us from the industrial zone," she said.

People.com.cn reported that people had been evacuated from companies and residential communities in the surrounding area.

A police officer from the industrial park told the Global Times that the fire was extinguished by the afternoon.

"Most staffers had returned to the spa by 3 pm," Yang said.

Calls to the plant and the industrial park management office went unanswered Monday.