It has a sky-blue-and-white striped flag stamped with a dove and a national anthem that speaks of “the heroes who bore the land with their blood.”

“Glory to the father for making you a nation, a joy forevermore,” the lyrics say. “Ambazonia, land of freedom.”

The nation of Ambazonia doesn’t officially exist. But a violent battle over attempts to create it in English-speaking areas of largely French-speaking Cameroon is quickly escalating. Schools, homes and villages in the Central African nation have been burned to the ground. Travel between some towns has been blocked.

For a year and a half, the Cameroonian military has been accused of beating and arresting people suspected of being separatists, torching homes and killing unarmed protesters.

For their part, separatists have taken up arms and have also turned to violence. They have been accused of burning markets, launching attacks from civilian bases, beheading soldiers and kidnapping people they suspect as traitors.

“We see the situation degenerating from a crisis to a conflict,” said Gaby Ambo, executive director of the Finders Group Initiative, a human rights group in Cameroon. “And if nothing is done soon, it will turn into a civil war with grave consequences.”

Anglophone separatists have been fighting for recognition of Ambazonia — named after Ambas Bay in southern Cameroon, an 1800s-era settlement for freed slaves — for decades. But calls for secession have amplified significantly in recent months.

So far Cameroon’s government has refused to engage in meaningful dialogue with separatists, largely because it flat-out rejects losing territory. Anglophone regions contribute to the nation’s economy and include important palm oil and other agricultural production.

“It is not possible to sit around the table with groups who would like to take the nation and cleave the nation,” said Issa Tchiroma Bakary, Cameroon’s information minister.

“Secession,” he said, carefully emphasizing every word, “this shall never, ever take place.”

Cho Ayaba, commander in chief of Ambazonian Defense Forces, who delivers orders from his home abroad, is convinced a section of the United Nations Charter gives Ambazonia status as its own nation.

“We are at a very, very dangerous crossroads,” Mr. Ayaba said. “The absence of willingness on the part of Cameroon to negotiate itself out of its occupation of Ambazonia and insistence on the utilization of disproportionate force leaves the Ambazonian people with no other choice than to defend themselves.”

English-speaking citizens of Cameroon make up about a fifth of the population in two of the nation’s 10 regions. Modern-day Cameroon is one of the most geographically, ethnically and linguistically diverse countries on the continent, so much so that it is known as “Little Africa.” But its two official languages, French and English, come from colonization.

Many Anglophones have long felt ignored by the French-speaking government, a sentiment dating to the post-World War I era when the League of Nations appointed France and England as joint trustees of what was then German Kamerun. The colonialists pushed their own cultures, languages, and legal and educational systems on their territories.

Independence for both territories came in the early 1960s with a reunification referendum that, over some objections, limited any option for Anglophone Southern Cameroon to become its own country. Instead, voters were allowed to choose only between joining either Cameroon or neighboring Nigeria. They chose Cameroon.

A move away from a federal model and political wrangling in the years that followed left some Anglophones feeling cheated out of power. Even a star representing English-speaking areas on Cameroon’s flag was removed at one point. In the early 1980s when Paul Biya became president, he further centralized power to French-speaking areas.

Many English speakers contend they have been marginalized by a government that has failed to give them resources and opportunities for years.

Aid workers and analysts attribute many of the problems to the fact that Mr. Biya, one of the continent’s so-called presidents for life, has been in office since the early 1980s. His entrenched grip on power in the French-speaking capital has made it difficult for anyone not in his orbit to climb the Civil Service or political ranks.

The new violence threatens to cast a shadow over presidential elections in October when Mr. Biya, 85, is seeking yet another term.

For years, the Anglophone separatist movement was largely waged from abroad by activists who fled the country during protests decades ago. It reignited in late 2016 when a group of lawyers and teachers protested the appointment of judges and teachers to their courts and schools who lacked strong English skills and a familiarity with the British-based systems in place in Anglophone regions.

Their rallies began to draw hundreds of citizens airing grievances. As they grew in size, the rallies turned violent, with the police firing on protesters. At least 20 were killed, some when security forces fired from helicopters, according to Amnesty International.

Several months ago, separatists in the Ambazonia Defense Forces took up arms to fight for sovereignty.

A report from Amnesty International says armed separatists have killed 44 members of the security forces since September, in one instance stabbing to death two police officers at a checkpoint. Separatists have attacked teachers and students not participating in a boycott of schools and have vandalized dozens of schools, burning at least two of them.

“Every day, there is more bad news,” said Col. Didier Badjeck, a Cameroonian defense spokesman.

The report says Cameroon’s security forces have arrested hundreds of activists and journalists, torturing nearly two dozen minors to extract confessions. Last year, Cameroon blocked the internet and cut phone lines for months. It jailed the self-declared interim president of the Federal Republic of Ambazonia and dozens of others after they fled to Nigeria and were sent back.

“It’s getting dire,” said Agbor Nkongho, founder and chairman of the Center for Human Rights and Democracy in Africa, who is based in Buea, Cameroon. “The average civilian is the one who’s suffering.”

Colonel Badjeck would not comment on specific abuses by the military but said that Cameroon’s armed forces respected human rights and that any reports of abuses were investigated, and perpetrators punished. The military has peacefully arrested separatists who put down their weapons, he said. “If they have their arms up, we will protect them,” he said.

But if not, Colonel Badjeck said: “We are military. We are going to shoot them. It is a war. You can’t go into a sovereign country and have weapons and shoot police and military. Even in the United States, if you see a terrorist who has a gun, the military is supposed to neutralize these guys.”

Mr. Bakary, the information minister, said that any abuses, including the burning of villages were being investigated.

“The responsibility of the army is to protect the lives and well-being and the property of our brothers and sisters who speak English,” said Mr. Bakary, who vigorously disputed the notion that the military was engaged in genocide. “It is unbelievable and unthinkable we willingly would turn the guns against our own people.“

Observers at human rights organizations who did not want to be identified because of security concerns have decried the use of the word genocide, saying that while it appears the military has carried out abuses it is not engaged in so-called ethnic cleansing. Cameroonian officials have neither talked of purging the nation of Anglophones nor said that Anglophones are not Cameroonian.

The officials have accused separatists of launching attacks from civilian bases and putting lives of innocents at risk.

Separatist leaders said attacks on civilians by any of their forces were unacceptable and would be investigated. But Mr. Ayabasaid attacks on security forces were legitimate.

“We want them to withdraw from our country,” he said. “Their presence is illegal. They have encroached within Ambazonia illegally and dismantled our economic, political and social system. They have engaged in systematic policies of torture political exclusion economic deprivation.”

Mr. Ayaba, who lives in Europe in a country he refused to identify because he fears for his safety, has been fighting for recognition of Ambazonia since he was a student in the 1990s living in Anglophone Cameroon and attending a university that he said was poorly equipped and neglected by the government. Back then he was involved in protest that turned violent and involved mass arrests.

Mr. Ayaba is one of several activists living abroad, many of whom were united in a peaceful pursuit of the creation of Ambazonia until recently.

The turn to violence prompted splits within the council.

“The situation may be running out of control,” said Edwin Ngang, who lives in Minnesota and is the senior presidential adviser of the Republic of Ambazonia and community organizer for the Ambazonia People’s Restoration Movement.

Mr. Ngang’s profile picture on WhatsApp is a poster for a pro-Ambazonia rally earlier this year in Hagerstown, Md., proclaiming “stop apartheid.” The word “genocide” is spelled out in dripping, blood-red letters.

Mr. Ngang and other separatists lament the lack of attention the crisis has received internationally.

“They’re waiting for the misery index to reach a certain scale before they intervene,” he said.

The United States ambassador to Cameroon has called on both sides to stop the violence and listen to each other.

Tens of thousands of people have fled the violence, some arriving across the border in Nigeria. Others still living in Anglophone areas are hunkered down, afraid. One of them, Peter Tafu, said his six children had not been to school in more than a year and a half.

“If my children go to school,” said Mr. Tafu, “I’m not sure they’ll come back home alive.”