Cameroon has admitted that soldiers acting alongside a militia shot dead 13 civilians, including 10 children, in the restive north-west of the country.
Officials had initially denied the army was involved in the killings in Ntumbo in February.
In a statement, Cameroon's presidency said three soldiers along with members of a vigilante group had stormed a separatist rebel base.
It suggested the deaths were accidental but soldiers tried to cover them up.
Cameroon's government has been fighting separatists in the region for three years.
At the time of the attack, the UN said 23 people had been killed including 15 children and two pregnant women. A tally by Human Rights Watch (HRW) said 21 civilians were killed, including 13 children and a pregnant woman, and blamed the attack on at least 10 troops from an elite army unit who were backed by "at least 30 armed Fulani" militiamen.
BBC World Service Africa editor Will Ross says this is an embarrassing U-turn for the government but there are still doubts about the official version.
The government had denied the army was involved but President Paul Biya responded to international pressure by ordering an investigation.
On Tuesday, a statement broadcast on state radio said soldiers and vigilantes stormed the rebel base and then discovered "that three women and 10 children were killed" in the gun battle.
"Overcome with panic, the three soldiers helped by some members of the self-defence group tried to hide the incident by setting fires," the statement added.
President Biya has ordered the arrest of the sergeant who led the raid, officials said.
Unrest in Cameroon has been centred in the north-west where most of the population speak English because of colonial-era ties to Britain.
Armed separatist groups began to emerge in 2017 after a government crackdown on protests. Separatists have declared independence for a new state they call Ambazonia, but President Biya has labelled the groups "terrorists".
More than 3,000 people have died since the outbreak of fighting and at least 70,000 people have also been displaced from their homes.
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