Hanoi: At least 21 people have died and scores more have been injured in an explosion at a fireworks factory in a military complex in northern Vietnam, an army official said on Saturday.
Plumes of black smoke billowed from the Z121 military facility, around 120 kilometres north of Hanoi, as fireworks exploded uncontrollably for several hours, witnesses said.
"Twenty-one people are dead and 98 others are injured -- most of them have sustained burns," a military rescue official told requesting anonymity and raising an earlier toll of seven dead.
The explosion prompted the evacuation of some 2,000 people living near the area.
"The fire has now been brought under control," a police official in Phu Tho province told, adding that an investigation into the cause of the accident had been opened.
"The first blast was at 7:55 am -- and then there were continuous explosions for some hours," Phi Xuan Trung, chairman of the local Khai Xuan commune, was told the VNExpress news site.
"There was a strong smell of gunpowder, the ground was shaking many kilometres away," he added.
Residents in Thanh Ba district -- where the complex is located -- also said they felt the ground shake during the powerful repeated explosions.
"After the first explosion, my house was shaking and the door smashed open," eye witness Nguyen Nhu Quynh told VNExpress.
Loudspeakers urged people within 15 kilometres of the military facility to leave the area.
One local resident told that locals have fled to the Viet Tri township, about 40 kilometres away.
"We have received warnings from authorities that there could be further explosions which could be very destructive," he said, speaking on condition of anonymity.
In 2010, fireworks being prepared at Hanoi`s My Dinh stadium for use in the city`s 1,000th anniversary celebrations exploded, killing three foreigners and one Vietnamese national.