A raging fire swept through a poultry slaughterhouse in northeast China on Monday, killing nearly 120 people who were reportedly trapped behind locked doors.

More than 300 employees were in the Baoyuan poultry plant in Jilin province when the blaze broke out following three early morning blasts triggered by a suspected chemical leak, the official Xinhua news agency said.

At least 119 people died in the inferno, while around 100 workers managed to escape. Rescue workers were uncertain if any remained trapped inside, saying the facility’s “complicated interior structure” and narrow exits hampered their efforts.

“It took less than three minutes for the whole of the workshop to go up in flames,” a plant worker told AFP. Reports say only one door to the plant was open while other exits were locked.

Survivors described panic inside the burning plant as employees scrambled to locate fire exits, some of which turned out to be shuttered.

Chinese President Xi Jinping and other top officials ordered that no effort be spared to rescue and treat survivors. Xi also vowed to investigate the cause of the incident, reports The Associated Press.