A fire killed 41 inmates in an overcrowded prison block in Indonesia’s Banten province on Wednesday, a government minister said, injuring scores more in a blaze that police said may have been caused by an electrical fault.

The fire, the country’s deadliest since 47 perished in a firework factory disaster in 2017, broke out at 1.45am, local time, in a Tangerang Prison block, said Indonesian law and human rights minister Yasonna Laoly, after visiting the scene.

“We’re working together with relevant authorities to look into the causes of the fire and of course formulating prevention strategies so that severe catastrophes like this won’t happen again,” the minister said. He said two of the dead were from South Africa and Portugal, and said the prison was operating above its capacity when the fire broke out.