A fire at a Vietnamese shoe factory killed 17 people and seriously injured 21 others in the northern port city of Hai Phong, state-controlled media reported on Saturday.
Thanh Nien newspaper quoted Bui Thi Them, one of the survivors, as saying the fire broke out Friday afternoon when welding sparks ignited roofing insulation.
The welder was installing a lightening rod on the factory's tin roof in preparation for a tropical storm that is expected to hit northern Vietnam later on Saturday.
The insulation fell to the factory floor in a fireball, blocking the 150-square-meter workshop's only entrance before quickly engulfing piles of shoemaking materials, it said.
"The fireball blocked the factory's main entrance and there is no exit on the back," Them told the paper. "Many people in the middle of the factory which was engulfed with fire and smoke could not escape and were burned to death."
Vietnam Television reported that 13 people were killed of burns and suffocation Friday and four others who were seriously burned died Saturday morning.
Eight other people who were in critical condition were transferred to a hospital in capital, Hanoi, it said.
The newspaper reported today that police have detained six people, including the Vietnamese owner of the factory, her Chinese husband and the welder, for questioning.
Tuoi Tre newspaper said six workers managed to escape unhurt.
It said the factory has been in operation for nearly a month.