Niger's main mine workers' union has thrown its support behind the military government's planned nationalisation of Somair, one of the world's largest uranium mines, saying output will continue, despite tensions with French operator Orano.

Niger, which seized the Somair mine in December, announced its plan to nationalise it last week, accusing Orano of taking a disproportionate share of production.

Its action follows measures by other West African governments to increase earnings from their natural resources.

French state-owned Orano did not respond to a request for comment on the allegations that it has taken more than its fair share.

It has previously said it opposes Niger's plan and that it reserves the right to take legal action.

The National Union of Niger Mine Workers, or SYNTRAMIN, said in a statement on Saturday that it backed the "sovereign decision" by Niger's military rulers, who seized power in a coup in 2023.

"For more than 50 years... the benefits of this strategic wealth have never fairly benefited Niger," it added, denouncing "decades of pillaging organised for the benefit of foreign interests," without providing evidence.

Orano holds a 63% stake in Somair, while Niger's state-owned Sopamin owns the remainder. The government said last week that Orano had taken 86.3% of production between 1971, when the mine was launched, and 2024, without elaborating.

SYNTRAMIN also pledged to "mobilise to ensure the continuity of production and optimal valorisation of our resources" under new state management.

Niger is the world's seventh-largest uranium producer and Somair plays a critical role in global nuclear fuel supply chains.