A fire broke out at a hospital for elderly patients in Jangseong, South Jeolla Province, early Wednesday, killing at least 21 and injuring seven. The dead include one nurse who was on night duty, authorities said. Six of the injured are said to be in critical condition.

The cause of the fire has yet to be determined, but witnesses have said that the fire started in an unoccupied room on the second floor of the building. 

According to reports, there were 35 people on the second floor of the building when the fire broke out, seven of whom managed to escape.

According to the authorities, the fire broke out about 0:27 a.m.

Although the fire services arrived at the scene within four minutes of the fire being spotted and the blaze was put at by 0:55 a.m., most of the dead were prevented from evacuating due to old age and medical conditions.

Most of the victims are said to have been in their 70s and 80s, and suffering from senile dementia or the side effects of stroke.

The authorities are also investigating whether the hospice was in practice of placing patients in restraints following witness accounts.

By Choi He-suk (cheesuk@heraldcorp.com)