At least 15 people have died when an artisanal gold mine collapsed in northwestern Burundi, an official said on Sunday.

The accident occurred in the Mabayi commune of Cibitoke province on Saturday, according to Nicodemus Ndahabonyimana, the commune’s administrator.

“The victims were operating in underground wells at an illegal mining site,'' he told reporters.

Rescue teams responded to rescue the victims but the operation ended ''in vain,'' he said.

Ndahabonyimana attributed the tragedy to the overflowing of the Rugogo River amid torrential rainfall, which flooded the pits.​​​​​​​

Mining disasters are often reported in Burundi’s northwest and northeast, where miners work at night to avoid oversight of authorities.