OUAGADOUGOU, Burkina Faso — The morning after the coup in Burkina Faso, a crowd of revelers celebrating the military takeover in the dusty main plaza of the capital had two messages for the outside world: No to France, and yes to Russia.

“We want a partnership with Russia,” said Bertrand Yoda, a civil engineer who shouted to make himself heard amid hundreds of horn-honking, cheering people gathered in a raucous show of appreciation for the new military junta. “Long live Russia!”

Mutinying soldiers seized power in this poor West African nation on Monday, riding a wave of boiling frustration at the government’s failure to stem surging Islamist violence that since 2016 has displaced 1.4 million people, killed 2,000 and destabilized perhaps two-thirds of a once-peaceful country.

But now that the democratically elected president, Roch Marc Christian Kaboré, has been sidelined — the military says he is being detained — coup supporters have turned to remaking Burkina’s Faso’s foreign alliances. Their preferences were broadcast in the Russian flags that fluttered in the capital, Ouagadougou, on Tuesday, alongside blunt, hand-painted signs aimed directly at Burkina Faso’s former colonial ruler.

“No to France,” one read.

The sudden clamor for Moscow’s help was a further sign of how Islamist violence across the Sahel, a vast region south of the Sahara, is upending old alliances and eroding pro-Western, if often weak, democratic political orders.

Many people at the protest said they were inspired by Russia’s intervention in the Central African Republic, where Russians guard the president, Russian companies mine for diamonds, and Russian mercenaries fought off an Islamist offensive last year — as well as a more recent Russian foray into Mali, the country to the north of Burkina Faso.

“The Russians got good results in other African countries,” Mr. Yoda said. “We hope they can do the same here.”

There are no Russian troops known to be in Burkina Faso, and it is unclear if the country’s new military ruler, Lt. Col. Paul-Henri Sandaogo Damiba, wants them to come. On Tuesday, The Daily Beast reported that Lieutenant Colonel Damiba had implored President Kaboré to hire the Wagner Group, a Kremlin-linked mercenary group earlier this month.

Several U.S. officials privately questioned this account, but said it was entirely plausible that the new military government could seek Russian assistance.

It wasn’t clear how Russian flags ended up at a pro-military demonstration in central Ouagadougou on Tuesday, less than 24 hours after the coup. The Russian Embassy in Burkina Faso could not be reached for comment on Tuesday. But the rally was one indication of an effort to pave the way for Russian intervention in yet another African nation.

“The difficulties Europe and in particular France have faced in reining in jihadist groups in the Sahel has provided an opportunity for Russia to expand its security cooperation, particularly in Mali,” said Andrew Lebovich, a policy fellow at the European Council on Foreign Relations, a research body.

Russian intervention in Africa often focuses on resource-rich countries in dire need of military help where Western influence is waning or absent, analysts point out. Russian help comes in the form of military advisers, weapons or mercenaries, paid for with cash or mining concessions for gold, diamonds and other resources.

The Russian presence is dominant in the Central African Republic, but Russia is also known to have intervened, to varying degrees, in Mozambique, Libya and Sudan, among other countries.

More recently, Russia’s focus has shifted to the Sahel, where it is taking advantage of growing anti-France sentiment and its own reputation for effectiveness in combat, Mr. Lebovich said. But he added, “the record of Russian private military companies in Africa and the Middle East is at best mixed, and marred by significant abuses.”

The United States also has a link to the Burkina Faso coup.

On Tuesday, the U.S. Africa Command confirmed that Lieutenant Colonel Damiba participated in numerous American military courses and exercises between 2010 and 2020, joining a long list of African coup leaders who received American military training.

Lieutenant Colonel Damiba received instruction on the law of armed conflict, civilian control and respect for human rights, Kelly Cahalan, a spokeswoman for the Africa command, said in an email. “Military seizures of power are inconsistent with U.S. military training and education,” she wrote.

The warm welcome received by Russia in some African countries contrasts sharply with the unfolding crisis in Ukraine, where the United States and its NATO allies fear an imminent invasion.

Even so, Russia has stirred a diplomatic hornet’s nest with its recent move into Mali, where the ruling military junta turned last fall to the Wagner Group in its fight against Islamists.

That deployment, which saw the first reported clashes between Russian mercenaries and Islamist fighters earlier this month, has infuriated France, which since 2014 has deployed thousands of troops to the Sahel, including Mali, to help its former colonies counter the growing terrorist menace.

But it piqued interest in Burkina Faso, where civilians and military officers who despaired of their own, French-backed efforts to fight the Islamists began to consider the Russian model as a viable alternative.

“We support the Russians,” said Aminata Cissé, a water seller who joined the crowds celebrating military rule. “Our families are dying, and unemployment is rising, yet France hasn’t helped much. At least we can try something new.”

Public opinion in favor of a Russian intervention gathered momentum on social media in recent weeks, several residents said. On Facebook, in particular, people in Burkina Faso reposted news accounts of the Russian deployment to Mali.

They also noted heated criticism by Malian leaders of France’s decision to draw down its troops and close three key bases in northern Mali since last October.

At the United Nations in September the interim prime minister of Mali, Choguel Kokalla Maiga, accused France of abandoning his country, saying it would force Mali to seek “new partners.”

In the crowd in Ouagadougou on Tuesday, several people said they were inspired by Mali’s defiance of France. They viewed Monday’s military takeover, and their desired pivot to Russia, as a chance to achieve “total independence” from France, which formally left Burkina Faso in 1960.

Analysts say this week’s coup has dealt a new blow to France’s faltering effort to stabilize the Sahel. But a senior French military official dismissed suggestions that Burkina Faso was about to swing abruptly toward Russia.

The fact that Lieutenant Colonel Damiba was trained in Paris, not in Moscow, means that France “should be able” to find a way to continue its decades-old cooperation with the army of Burkina Faso, said the official, speaking on the condition of anonymity to discuss national security issues.

But, he added, “We’ll have to be active to avoid any vacuum the Russians could exploit.”

Eric Schmitt contributed reporting from Washington.