Twelve people have been rescued from an informal gold mine in eastern DR Congo that collapsed over the weekend, trapping an unknown number of the thousands of miners working there, the provincial governor said Wednesday.

The Lomera gold mine in the South Kivu province collapsed on Sunday following a landslide, burying numerous miners working in the underground tunnels, Governor Patrick Busubwa Ngwi Nshombothe said in a statement following his visit to the site.

Nshombothe said over 4,700 miners work on the site and the death toll and number of miners missing are unknown. Search and rescue efforts continue.

The South Kivu region has recently been hit by heavy rains, triggering landslides in several villages and mining sites.

The Lomera site is an artisanal mine, operated not by a formal company but by individual workers using basic tools.

It is located in a territory controlled by the M23 rebels who seized two large parts of mineral-rich eastern Congo in a major advance early this year.