War, Mediation or Silence? Deadline for Coup Leaders in Niger Passes.

Stocking up on rice, fleeing the capital by bus or vowing to defend their new military leaders, many in Niger braced this weekend for a deadline imposed by a 15-member bloc of West African nations for the country’s junta to relinquish power.

But that deadline to restore democracy or face military action expired on Sunday.

After mutinous soldiers detained Niger’s democratically elected president on July 26, the Economic Community of West African States, or ECOWAS, gave the junta the ultimatum, raising fears of a regional conflict in a part of Africa that includes some of the world’s poorest countries and that is already plagued by Islamist insurgencies, widespread food insecurity and the extreme effects of climate change.

But the ultimatum also rallied many Nigeriens behind their new military leaders. On Sunday, tens of thousands of defiant junta supporters thronged the largest stadium in the capital, Niamey, voicing their anger against ECOWAS and chanting the name of the military official who claims to be in charge, Gen. Abdourahmane Tchiani.

West African officials said that they would employ force only as a last resort, and most analysts said that a conflict appeared unlikely, at least in the near term. But ECOWAS military officials said that they did have a plan for an intervention, if needed.

“Democracy must be restored, through diplomacy or force,” Gen. Christopher Gwabin Musa, the Nigerian chief of defense staff, said on Saturday in a telephone interview.

But the mutineers who were holding the president, Mohamed Bazoum, said they would resist any effort to remove them from power, leaving Niger’s future — and that of its people — hanging in the balance. On Sunday, the country closed its airspace, citing the potential threat of outside military intervention.

Asmana Rachidou, 33, a father of six, was shopping for milk powder and packets of rice in downtown Niamey, Niger’s capital, on Saturday. Prices have soared since ECOWAS imposed financial sanctions on the country. “If ECOWAS strikes, it will be over for us all, not only for the military,” Mr. Rachidou said.

Mr. Bazoum, a key Western ally who was elected in 2021, has refused to resign, and the military officials in charge have so far ignored calls to release him. They have also rebuffed threats by the United States and the European Union to cut ties, instead turning toward two neighboring countries, Burkina Faso and Mali, that have also had coups in recent years and have since moved closer to Russia.

On Sunday, Mr. Bazoum remained stranded with his family in their private residence without electricity or water, according to a friend and adviser of the president who requested anonymity to discuss the president’s situation. Nigeria, which provides about 70 percent of Niger’s electricity, has suspended its energy supply, throwing most of the country into the dark. The president’s guards confiscated his cellphone SIM cards on Saturday, according to the friend, leaving Mr. Bazoum unable to communicate with the outside world as he had done in the first days of his captivity.

The stalemate in Niger has also thrown into uncertainty the future of more than 2,500 Western troops stationed in the country for counterterrorism purposes, including about 1,100 Americans. Unlike neighboring countries, including Burkina Faso and Mali, where groups affiliated with Al Qaeda and the Islamic State have carried out hundreds of attacks and now control large swaths of territory, Niger has been faring better, with civilian deaths decreasing this year.

Modou Diaw, a humanitarian worker who traveled to Niger last month, said that he had been able to visit areas that were previously impossible to reach because of the insecurity. “The situation was really improving,” said Mr. Diaw, vice president for West Africa at the International Rescue Committee, an aid organization, adding, “All these gains are now being threatened by this situation.”

The impasse could also send millions of Nigeriens further into poverty and instability, because their country depends on foreign aid for 40 percent of its national budget.

Still, this weekend, hundreds of young people struck a defiant tone in downtown Niamey, vowing to defend the junta against any foreign intervention. On Saturday, they stood guard at the city’s roundabouts, checking cars for evidence of foreign meddling and spying, acting on a warning from the junta of such activity.

Many Nigeriens, in a sign of patriotism, have also set the country’s tricolor flag as their profile picture on the WhatsApp messaging platform.

But other Nigeriens have been making plans to hunker down or even to escape the capital. On Saturday, residents of Niamey flocked to shops to stock up on cooking staples, like rice and oil, in the event of a military intervention. Middle-class families, unable to turn on their air-conditioners during one of the year’s hottest periods, have rushed to buy mosquito nets to set up camps in their courtyards.

And many others, expecting fighting in Niamey, have fled the capital to elsewhere in Niger. Minata Abid, 22, a student majoring in human resources at the University of Niamey, left by bus late Friday night with her twin sister and only some of their belongings — packed up in two suitcases — after their mother saw social media posts about a possible military intervention and ordered them home.

They arrived on Sunday in Arlit, about 500 miles northeast of Niamey, happy to see their family again but concerned about when they would be able to return to school, Ms. Abid said. “I worry about my future,” she added.

General Musa, the Nigerian military official, said that ECOWAS countries wanted a peaceful resolution of the situation and were not warmongers.

“There’s no need for a war. This would bring more destruction,” he said. Referring to Niger and Nigeria, General Musa added, “Culturally, religiously, we’re almost like the same. It would be like fighting your brother.”