Niger's military-appointed prime minister on Monday said he saw hopes of a deal "in the coming days" with the West African bloc Ecowas, which has threatened to use force to restore civilian rule after a coup in July.

He also said that "contacts" were underway over a "very swift" pullout of French forces from Niger after ties with France spiralled downwards following the military takeover.

"We have not stopped contacts with Ecowas, we are continuing contacts. We have good hopes of reaching an agreement in the coming days," Prime Minister Ali Mahaman Lamine Zeine told a press conference in Niamey.

Ecowas -- the Economic Community of West African States -- has slapped hefty sanctions against Niger after rebel soldiers on July 26 overthrew Mohamed Bazoum, the country's democratically elected president.

It has also warned several times of intervening militarily to reinstate Bazoum should diplomatically attempt to resolve the crisis fail.

"We are bracing to be attacked at any time. Every preparation has been taken. It would be an unjust war. We are determined to defend ourselves if there is an attack," Zeine told reporters.

A key question in the crisis is a timeline for returning to civilian rule.

Nigerian President Bola Tinubu -- who is also the current chairman of Ecowas-- last Thursday suggested a nine-month period such as his country underwent in the late 1990s.

"The president sees no reason why such cannot be replicated in Niger, if Niger's military authorities are sincere," the Nigerian presidency said in a statement.

Algeria, Niger's influential northern neighbour, has proposed a six-month transition

The military rulers have so far not responded to the suggestions, having previously spoken of a three-year hand back period.

Ecowas has taken a hard line with regard to Niger following a cascade of coups in its region since 2020.

The military have taken power in Mali and Burkina Faso, where like Niger, losses among the armed forces are surging in the face of a long-running militia insurgency.

A putsch also took place in Guinea in 2021 after the country's octogenarian president, Alpha Conde, ran for a third term in office, a move that opponents said breached constitutional limits.

In other comments, Zeine said, without elaborating, that "contacts" were underway "that should enable a very swift withdrawal of French forces" from the country.

But, he said, Niger wished "to maintain cooperation with a country with which we have shared an enormous number of things."

Tensions between Niger and its former colonial power and ally in the fight against militias insurgents ratcheted up after France stood by the ousted Bazoum.

Paris has refused to acknowledge the coup leaders as the legitimate government and ignored announcements cancelling military agreements with France and a threat to expel the French ambassador.

France has around 1,500 troops in the Sahel state, many of them deployed at an air base near the capital Niamey.

Tens of thousands of protestors rallied outside the base at the weekend to demand they leave, responding to a call by a pro-coup civilian coalition.

The post-coup government on August 3 renounced military accords with Paris, a move France has ignored.

Zeine said that as a result of the renunciation, the French troops in Niger are now "in a position of illegality".

One of the accords required a notice period of one month, according to military sources.

Meanwhile, Niger reopened its air space on Monday after imposing a flight ban on August 6 in response to the Ecowas threat, the official news agency ANP said.

Some flights to Niamey were permitted during this time, with special authorisations.

Air France told AFP that it would resume flights over Nigerien territory from Tuesday morning, although its air services to and from Niamey would remain suspended until further notice.

Separately, the Chinese ambassador in Niger said that Beijing hoped to play a "mediating role" in the political crisis, in comments broadcast on Nigerien television.

"The Chinese government intends to play a role of good office, of mediator... to find a political solution to this Nigerien crisis," said Jiang Feng, Chinese ambassador to Niger, adding that China "always supports African countries to resolve their problems the African way".

China is a major economic partner for Niger, particularly in the energy sector, including building the longest oil pipeline in Africa.