Niger’s military government has revoked the operating licence of French nuclear fuel producer, Orano, at one of the world’s biggest uranium mines, the company said on Thursday.

The decision has highlighted tensions between the junta, which came to power in a coup in July last year, and the former colonial power, France.

The military seized control of Niger on the pledge of cutting ties with the West, vowing to review mining concessions in the country, and ordering the withdrawal of Western troops.

Orano said it has been told to leave the Imouraren mine in northern Niger, which sits on an estimated 200,000 tonnes of uranium that is vital for producing nuclear energy.

Mining was due to have started at the site in 2015, but development was halted after the collapse in world uranium prices in the wake of the 2011 Japanese nuclear disaster.

Following years of delays, Niger had warned the licence would lapse on 19 June unless work resumed at the site.

Thursday’s decision by the Nigerien junta comes “despite the resumption of activities on site, pursuant to the expectations they had expressed,” Orano said in a statement.

In a letter to the company dated 20 June, seen by the Associated Press, the Nigerien mining ministry said Orano’s exploitation plan “did not meet our expectations”.

As a result, the mine has been “returned to the public domain” and exempted from all contractual rights, the letter said.

Since coming to power, the junta has been reducing its ties to France.

After expelling Paris’ ambassador, Niger in December ordered the departure of French troops deployed to fight Islamist militants in the region.

The junta has been establishing closer links to Russia.

Orano, which has been operating in Niger for over 50 years, said it was “willing to keep all channels of communication open” with the military authorities.

But it added that it reserved the right to take legal action against the withdrawal of the operating licence in a national or international court.