YAOUNDE — Cameroon's army on Monday denied opposition charges that it had massacred villagers in a restive anglophone region, blaming instead an "unfortunate accident" caused by an explosion of fuel during a firefight.

Up to 22 civilians, 14 of them children, died in the incident on Friday, according to the United Nations — deaths which opposition parties blamed on members of the armed forces.

But army spokesman Colonel Cyrille Atonfack Guemo described the allegations as "duplicitous".

An army investigation found that the deaths happened when fuel exploded in an exchange of gunfire with anglophone separatists and caused a fire, he said.

Five civilians — a woman and four children — died, and "seven terrorists" were "neutralized," Atonfack said in Libreville by phone.

The deaths occurred in the village of Ntumbo in Cameroon's Northwest Region — one of two English-speaking regions that have been grappling with violence since October 2017.

Fighting between separatists campaigning for a separate anglophone state in French-speaking Cameroon has left around 3,000 people dead and caused more than 700,000 to flee their homes.

"It was quite simply an unfortunate accident, the collateral result of security operations in the region," Atonfack said in a statement.

He said four soldiers and two gendarmes had been carrying out nighttime reconnaissance on foot near a home that had been "transformed into a fortress" with a stockpile of weapons.

They came under heavy fire, and exchanges caused "several containers of fuel to explode, followed by a blaze which spread several neighboring homes."

The army had previously denied any involvement in the deaths.

On Sunday, James Nunan, a local official with UN humanitarian coordination agency OCHA, said that armed men had carried out the killings.

"Up to 22 civilians were killed, including a pregnant woman and several children," Nunan said, adding that 14 children — including nine under age five — were among the dead.

Eleven of the children were girls, said Nunan, head of OCHA's office for the Northwest and Southwest regions.

The Movement for the Rebirth of Cameroon (MRC), one of the country's two main opposition parties, issued a statement condemning the attacks.

"The dictatorial regime (and) the supreme head of the security and defense forces are chiefly responsible for these crimes," it said.

A key figure in the separatist movement, lawyer Felix Agbor Mballa, in a Facebook post also accused "state defense forces" of carrying out the killings.

Years of grievances at perceived discrimination by the francophone majority snowballed into a declaration of independence by anglophone forces in October 2017, to which the government responded with a crackdown.

The declaration of independence has not been recognized internationally, although the government has lately responded to the crisis by decentralizing some of its powers.

Friday's killings followed elections on Feb. 9 that were marred by violence in the regions blamed both on separatists and security forces.

Armed separatists prevented people from voting, threatening reprisals, while government soldiers were a heavy presence.

Separatists kidnapped more than 100 people and torched property in the run-up to the elections, Human Rights Watch (HRW) said.

The government has not yet announced the results of the elections or turnout figures.

The UN refugee agency said on Thursday that almost 8,000 people had fled into Nigeria from Cameroon in the previous two weeks to escape fighting between security forces and armed separatists.

The latest arrivals brought the number of refugees to almost 60,000, the UN High Commissioner for Refugees (UNHCR) said in a statement.

"Refugees reported fleeing violence and some even arrived across the border with gunshot wounds," it said. — AFP