U.S. officials say the situation is “dynamic,” with both sides exploring conditions under which the American military presence could continue. That presence, which could be reduced, currently includes about 1,000 troops and a large drone base in the north of the country at Agadez that have been part of efforts to counter Islamist militancy in the region.

A spokesman for Niger’s junta said in a statement read on national television Saturday night that the U.S. military presence violates Niger’s constitution and that the government was ending, effective immediately, its security agreements with the United States. Amadou Abdramane, the spokesman for the National Council for Safeguarding the Homeland (CNSP), said the decision followed days of meetings in which a delegation of American officials in Niamey had displayed a “condescending attitude” and tried to dictate which countries the West African nation could have relationships with, including Iran and Russia.

The junta’s statement made public concerns raised privately by the Biden administration that Nigerien leaders had agreed to supply uranium to Iran, crossing what Washington considers a red line. And in December, Niger signed a new security agreement with Russia, but it is not yet clear what is involved, and Russian soldiers are not currently on the ground in Niger.

A senior U.S. official said the Biden administration believes the junta’s statement was “less some sort of principled stand against U.S. assistance than it was a fit of pique over the deep concerns we expressed to them last week about the direction they’re moving on a number of fronts.”

Some regional analysts say there are few grounds for optimism about the U.S.-Nigerien relationship. The Nigerien junta has not yet set a timeline for a restoring democracy as the United States insists — Niger’s elected president was overthrown in July — and appears unwilling to listen to the United States about whom it can partner with. Abdramane said Saturday that Niger’s relationships with Russia and Iran go back decades, and he defended Niger’s right to have relationships with whichever countries it chooses.

The junta’s strong words have already sparked calls within Nigerien society for American troops to depart. Local frustrations have previously focused on France, the former colonial power in Niger, but Nigeriens are increasingly questioning the purpose of the American troops.

These developments have left in limbo U.S. service members at the drone base, which Gen. Michael E. Langley, who heads U.S. Africa Command, said in a recent interview has been key for “active watching and warning, including for homeland defense.”

The Nigerien government did not respond to repeated requests for comment.

The U.S. military began operating in Niger during the early 2000s as part of the Bush administration’s counterterrorism strategy, mostly providing training and equipment for the country’s military, and expanded significantly around 2013, when Islamist militants seized vast swaths of territory in neighboring Mali.

At the peak of operations, around 2017, American forces were providing intelligence about armed groups as well as medical and logistical support on “kill and capture” missions led by the Nigerien troops, said Alan Van Saun, the company commander of a Special Forces battalion from summer 2017 to February 2018. He said all operations were carried out at the request of the Nigerien military and with permission from the U.S. Embassy in Niger, which differentiated the mission from those in Iraq or Afghanistan, where the U.S. military had more autonomy.

Since four American soldiers in Van Saun’s company were killed during the Tongo Tongo ambush in October 2017, prompting congressional and Defense Department investigations, military operations have been constrained. That has contributed to an “erosion of trust” with the Nigeriens, he said, “because when push comes to shove and it is time for them to go out the door and do the high-risk missions, we are sitting there keeping the lights on.”

Still, he added, a full-scale withdrawal of American troops would add to the growing security vacuum in the region, which in recent years has become a hot spot for Islamic extremism worldwide.

Following military takeovers in Mali and Burkina Faso in 2021 and 2022, respectively, junta governments asked French troops to leave and welcomed Russian fighters. In Mali, they are fighting alongside the army, while in Burkina Faso, they are providing training.

In the wake of those coups, Niger became an increasingly valuable Western security partner. When Nigerien military officers ousted democratically elected President Mohamed Bazoum last summer, many officials in Paris and Washington were shocked, with France backing a military intervention to restore Bazoum to power and the United States coming out against the idea.

Within weeks, the junta government had publicly demanded that French troops pack their bags by the end of 2023. The vast majority of U.S. security cooperation was put on pause, with operations limited to force protection and warning Nigerien officials about imminent militant attacks.

The junta’s announcement this weekend that it was severing security agreements with Washington followed a visit last week by a U.S. delegation including Langley; Molly Phee, the State Department’s top official for African affairs; and Celeste Wallander, assistant secretary of defense for international affairs.

During the meetings in the Nigerien capital, Niamey, the U.S. officials again stressed the importance of a transition back to democracy and said that Niger’s pursuit of partnerships with some other countries would limit the willingness of the United States itself to partner with Niger, according to a senior Biden administration official. The goal of the trip, the official said, was to determine “whether these guys can be a good partner to us and address our values and interests.”

Now, the situation in Niger is fluid, according to six senior U.S. officials, who spoke on the condition of anonymity because of the sensitivity of the issue. One official said that despite the public statement, the Nigerien government has not offered the private, technical communications that would force the U.S. presence out of the country.

Andrew Lebovich, a research fellow with the Clingendael Institute who focuses on Niger, said that there appears to be a failure among U.S. officials to “acknowledge reality in Niger.” Despite the massive American economic and security investments in the country over the years, he said, Nigerien officials now appear to show little interest in maintaining the American presence.

“For so long in Niger, the United States convinced itself that we are not the French and that we could count on Niger,” Lebovich said. “Now, there is an element of denialism in thinking U.S. troops might be able to find a way to stay.”

J. Peter Pham, a former U.S. special envoy for the Sahel region, said regional dynamics have changed. “It is no longer business as before,” Pham said. “One cannot approach African governments — even one of the poorest, least developed countries, like Niger — with lectures about democracy without first weighing our strategic interests and the immediate concerns of the regime.”

In Niamey, some residents said they worried that ending the relationship with the United States would lead to escalating violence. But others said they made no distinction between American troops and those from other countries, including France.

“We are really very happy to see this historic decision that the CNSP has taken to free our people from American imperialism,” said Alkassoum Saïdou, 36. “Each country defends its own interest, and not that of Niger.”

Omar Hama Saley in Niamey, Niger, contributed to this report.