At least 21 people died and several were injured Saturday in an explosion at a fireworks factory in northern Vietnam, local media said.

Authorities said that thousands of people have been evacuated from the scene of the accident in Phu Tho province while the search for victims continues, according to the daily Thanh Nien News.

Gen. Le Quang Dai, head of the military-run fireworks factory, said that scores of workers were on hand when the explosion occurred and that most were able to escape.

Police and soldiers are investigating the causes of the accident and helping provide aid at the factory, located some 120 kilometers (75 miles) north of Hanoi. EFE