Fourteen people have been killed in a tin mine in eastern Rwanda after a hill collapsed on them following heavy rains, officials said.

"Because of recent rainfall in the area, part of the hill nearby collapsed and 14 miners who were getting ready for work were buried by land," Fred Mufuruke, governor of Eastern province, told Reuters news agency on Monday.

Jean Claude Rwagasana, another local official from the Mwulire region, said the fatalities include seven women.

"This is an unfortunate event that nobody expected. The accident happened when falling debris at the mining site buried all the 14 people and killed them instantly," he told AFP news agency.

The accident took place at a cassiterite mine, a mineral which, along with the metallic ore, coltan, is a vital component for the production of mobile phones, digital cameras and electronic products.

The open mining site is owned by the Rwandan business of Britain's Piran Resources, said John Kanyangira, director of mining inspection at Rwanda Mines, Petroleum and Gas Board.

Kanyangira told Reuters that Rwanda's mining industry, quarrying excluded, employs 43,000 people.

Earnings from Rwanda's mineral exports more than doubled to $373m in 2017 up from $166m a year before. The government said revenues are expected to climb to $600m.

Small-scale mining in Rwanda's hilly landscape has led to landslides and mine collapses. Kanyangira said 81 people died in 2018 in various mining accidents.

In October, eight people were killed and four wounded in a mine collapse in southern Rwanda's Muhanga district.

Last month, at another mining site in southern Rwanda, five miners were trapped underground when the site collapsed. Soldiers and member of the public dug them out alive after nearly two days.

Rwanda's mining board has blamed the mining industry for the deaths, saying many mines' underground tunnels lack support and that firms are slow to implement safety standards.