The West African country had demanded that French troops leave. France confirmed they would be out in a month.

French troops in Burkina Faso will leave the West African country within a month, officials in France said on Wednesday afternoon, in the latest deterioration of relations between France and a onetime African ally.

Anne-Claire Legendre, the spokeswoman for the French foreign ministry, said France had been notified by Burkina Faso’s government on Tuesday that it was withdrawing from a military accord struck in 2018, and that therefore France had a month to leave the country. France would “respect the terms” of the accord, she said.

Earlier this week, a spokesman for the government of Burkina Faso told the country’s national broadcaster that it was terminating the agreement that allowed French forces to stay. Around 400 French troops, including 200 special forces, are thought to be stationed in the landlocked country, which has been turned upside-down in the past seven years by jihadist attacks and the fallout, including thousands of killings, mass displacement and hunger.

“This is not the end of diplomatic relations between Burkina Faso and France,” the spokesman, Jean-Emmanuel Ouedraogo, told the broadcaster, RTB, on Monday.

French officials have not confirmed the number of troops, however, and it remains unclear where they may move. In Africa, France has bases in Djibouti, Gabon, Ivory Coast, Niger and Senegal. President Emmanuel Macron of France is expected to announce a restructuring of France’s military presence on the continent later this year.

The departure of the French troops epitomizes a broader malaise developing between Burkina Faso and its former colonizer, a phenomenon spreading in Francophone countries in Africa. In Mali, Burkina Faso’s northern neighbor, thousands of French troops spent nearly a decade fighting extremists, but security did not improve, and the reach of the armed groups spread from its desert north to its more highly populated center. Malians blamed the French for the dire situation in their country, and last year, the French ambassador and several French media outlets were thrown out, while all of its troops were withdrawn under heavy pressure from the Malian government.

A similar scenario has unfolded in Burkina Faso, where Islamist militants have made inroads since 2015 and threatened to destabilize neighboring countries. In recent months, analysts and officials have warned that Burkina Faso could turn to the Russian mercenary group Wagner to reclaim lost territories, a scenario that in Mali has brought some results on the ground but also led to scores of civilian deaths.

In December, President Nana Akufo-Addo of Ghana accused the authorities in Burkina Faso, Ghana’s neighbor, of having signed an agreement with Wagner. “To have them operating on our northern border is particularly distressing for us in Ghana,” Mr. Akufo-Addo said.

That presence, however, hasn’t been confirmed.

Gen. Didier Castres, a former deputy chief of staff for operations in the French military, previously stationed in neighboring Mali, echoed Mr. Ouedraogo’s statement. “As long as Wagner doesn’t step in, I think France will keep the doors open,” he said.

A U.S. Defense Department official said earlier this month that he was “really concerned” that Burkina may turn to Wagner. “I don’t have a smoking gun, but we know how this goes,” the official said, citing a recent trip to Moscow by Burkinabe officials. The official, who spoke on condition of anonymity, also accused Wagner of carrying out disinformation campaigns to undermine France’s presence in Burkina Faso.

On Wednesday, a senior French official said the decision could accelerate other partnerships initiated recently by the Burkinabe authorities with countries such as Russia, Iran or even Turkey. Wagner, the official said, will likely take advantage of the situation to renew its service offer to the Burkinabe authorities. In September, the head of the group, Yevgeny Prigozhin, said Wagner was standing ready to help Burkina Faso’s new military junta, which seized power in a coup.

While France’s presence in Mali and Burkina Faso vanishes, it is beefing up its boots on the ground in Niger, another mostly desert country plagued by extremists, which is seen as a valuable Western ally in the Sahel, the arid strip of land that stretches across the continent south of the Sahara.