The African Union said Tuesday that it had suspended Niger’s membership in the wake of a military coup, but responded cautiously to a threatened military operation to restore its ousted president, as Nigerien TV said 12 soldiers were killed in a new attack by suspected jihadists.

National guards carrying out an anti-jihadist operation in the southwestern region of Tillaberi were ambushed on Sunday night, the broadcaster Tele Sahel said, adding that the troops inflicted “heavy losses” on the enemy.

Niger’s armed forces, struggling with an eight-year jihadist insurgency, have lost at least 29 men since officers toppled elected president Mohamed Bazoum on July 26.

The coup — justified by its leaders over Bazoum’s alleged failure to stem the insurgents — triggered a bustup with France, Niger’s staunchest ally, and the Economic Community of West African States (ECOWAS).

ECOWAS has imposed trade sanctions on Niger and approved the deployment of a “standby force to restore constitutional order” in Niamey.

The bloc is hazy about the plan in detail but insists it will intervene if attempts at a diplomatic solution ultimately fail.

As the crisis neared the end of its fourth week, the AU said Tuesday that it was suspending Niger from its ranks but indicated reservations about the ECOWAS threat following strong differences among its members.

The AU said its Peace and Security Council had asked the body’s Commission to carry out “an assessment of the economic, social and security implications” of deploying the force.

The coup has heightened international worries over the Sahel, which faces growing jihadist insurgencies linked to Al-Qaeda and the Islamic State group.

Niger is the fourth ECOWAS nation since 2020 to suffer a coup, following Burkina Faso, Guinea and Mali.

The country’s new military ruler, General Abdourahamane Tiani, has proposed a three-year transition back to democracy, a call rejected by ECOWAS, which sent a delegation to visit Niger on the weekend in a renewed diplomatic push.

Unlike a previous ECOWAS mission in early August, the envoys held talks with Tiani and also met Bazoum, who is being held with his family at the presidential palace.

Delegation chief and former Nigerian president Abdulsalami Abubakar gave a positive assessment of the talks.

“I must say that our visit to Niger has been very fruitful and that it has opened an avenue to start talking, and hopefully we’ll get somewhere,” he said.

But Abdel-Fatau Musah, ECOWAS commissioner for politics and security, described the three-year transition proposal as “a joke” and said the bloc would “never accept it”.

“We want constitutional order to be restored as soon as possible,” he told Al Jazeera in an interview broadcast on Monday.

“Military action is not off the table,” he warned.

In Johannesburg, on the sidelines of the BRICS summit, China’s Wu Peng, Africa affairs director-general at the foreign ministry, emphasised Beijing’s policy of “non-interference”.

“This kind of problem in Niger should be solved through peaceful dialogue through ECOWAS and the African Union,” he said.

The AU communique said it “strongly rejects any external interference by any actor or any country outside the Continent… including engagements by private military companies.”

Russia’s Wagner group is the most prominent paramilitary group active on the continent.

The UN’s World Food Programme (WFP) warned last week that sanctions and border closures were crimping vital food and medical supplies into Niger.

ECOWAS has imposed sanctions while Benin and Nigeria have closed their borders.

However, the juntas in neighbouring Burkina Faso and Mali have said that any military intervention in Niger would be considered a “declaration of war” against their countries.

Around 300 trucks arrived in Niger’s capital of Niamey on Monday from Burkina Faso, most of them carrying food, the Nigerien authorities said.

The Sahel state ranks among the most turbulent and poorest countries in the world, often lying at the bottom of the UN’s Human Development Index, a benchmark of prosperity.

In an article for France’s conservative Le Figaro newspaper Tuesday, Bazoum’s Paris-based daughter Zazia Bazoum Mohamed said her father, in refusing to resign, had “decided to fight to save democracy”, while urging his release.

Bazoum’s election in 2021 was a landmark, opening the way to the country’s first peaceful transition of power.

He survived two attempted coups before finally being toppled in what marked the fifth putsch since Niger gained independence from France in 1960.