This article was published by Reuters:

A mob lynched a military police officer after he killed a five-year-old girl when he fired on a car at a checkpoint in the capital of Cameroon's English-speaking South West Region on Thursday, the defence ministry said.

The girl's death sparked protests in Buea, with demonstrators marching her body to the regional governor's office. Sporadic gunfire also erupted in town, although it was unclear who was shooting.

Secessionist fighters angry about perceived marginalisation by Cameroon's French-speaking majority have been battling government troops in two English-speaking regions for nearly five years in an attempt to form a breakaway state called Ambazonia.

Over 3,000 people have been killed and nearly a million displaced, with both sides accused of committing atrocities.

The ministry said in a statement that the vehicle's driver initially refused to stop at a gendarmerie checkpoint and then tried to pull away from the officers who had managed to force him to a halt.

"In an inappropriate reaction, unsuited to the circumstances and clearly disproportionate to the irreverent behaviour of the driver, one of the gendarmes... fired warning shots in order to immobilise the vehicle," the statement said.

"In the process, the little Caro Louise Ndialle, a young pupil aged about 5, who was on board the said vehicle, was fatally shot in the head."

A crowd then set upon the gendarme and killed him, the ministry said, adding that an investigation has been opened into the two deaths.

Hundreds of residents took to the streets of Buea, some holding tree branches in a sign of peace. Others waved 500 franc CFA currency notes ($0.88), which they said was how much the girl's parents refused to pay before the gendarme opened fire.

Several said the incident was part of a pattern of heavily militarised security forces harassing local residents.

"All they do is intimidate people. If you have an identity card, it's a problem. If you don't have an identity card, it's a problem," said one protester, who declined to give her name for security reasons.

The regional governor office promised swift action as he tried to calm the crowd that had marched to his office.

"How is it that a child on her way to school is killed?" Governor Bernard Okala Bilai said. "Rest assured that those who did it will pay. It is an atrocity."