Niger's military rulers on Friday ordered the French ambassador to leave the country in the next 48 hours, but said a letter calling for a similar order for the US ambassador was fake.

A US State Department spokesperson said "no such request has been made to the US government," Reuters news agency reported.

The spokersperson added that Niger's Foreign Ministry told the US government that a widely-circulated letter online, calling for the US ambassador to be expelled, was not released by it.

Reports earlier stated that Niger's coup leaders had also asked the ambassadors of Germany and Nigeria to leave the country in the next 48 hours.

The AFP news agency reported that these reports were declared "unauthentic by authorities."

What the military junta said on France

The junta said the French ambassador had refused an invitation to meet with Niger's junta-appointed foreign minister on Friday.

The Foreign Ministry said the actions of the French government were "contrary to the interests of Niger."

But France said Niger's "putschists have no authority" to expel its ambassador in Niamey.

"The putschists do not have the authority to make this request, the ambassador's approval coming solely from the legitimate elected Nigerien authorities," Paris said, adding: "We are constantly evaluating the security and operating conditions of our embassy."

Niger was key ally in fight against extremism in Sahel

Niger gained independence from France in 1960 and had been a key ally in Western campaigns against insurgents linked to al-Qaida and the Islamic State group in the Sahel.

There are concerns that the coup could open the door to greater Russian influence there.

France and the US have around 2,500 military personnel in the country who have been involved in training and conducting joint operations against Islamist insurgents.

But those security operations, as well as financial aid from the countries, have been suspended following the coup.

The German Foreign Ministry earlier this month said it supports regional efforts to resolve the crisis in Niger, saying the aim was to restore constitutional order.

Berlin has called on the European Union to impose sanctions on coup leaders.