At least 50 people have been massacred by machete and axe-wielding attackers in eastern Democratic Republic of Congo, according to activists.
Witnesses said the killings were carried out by men in uniforms posing as soldiers.
The massacre happened near the Ugandan border around 6 miles (10km) from the town of Beni, where army and UN troops are stationed.
Government officials blamed a Ugandan Islamist rebel group, the ADF.
More than 200 people have been killed near Beni since early October by the ADF (Allied Democratic Forces), officials say.
It is not yet known exactly how many people died in the latest onslaught, reports the BBC's Maud Jullien in Kinshasa.
Nor is it clear, despite government accusations, which group is responsible for the deaths.
One woman who managed to flee said she counted at least 50 bodies, our correspondent adds.
Amisi Kalonda, the regional administrator, told the BBC that nine bodies had been retrieved so far.
He said the dead were spread out across the forest and that searches were still ongoing.
UN officials, who have been repeatedly criticised for failing to stem the violence, say they have increased their military presence in the area since October.
Analysis: Maud Jullien, BBC DR Congo correspondent
The spree of massacres near Beni started in October. The violence has been extreme - women, children and babies smashed against walls or slaughtered with machetes. No-one knows why. It remains difficult to get a clear picture of who is behind the killings.
The government says a rebel group from Uganda, the ADF-Nalu, is responsible. But a recent parliamentary report into the violence found that a Congolese army major threatened to shoot any troops under his orders who tried to stop a massacre. UN officials also say they suspect high-ranking members of the army of being complicit.
Meanwhile, and perhaps as a consequence, nothing significant seems to have been done to curb the extreme violence. Timid Congolese army offensives against the group have failed to stop the violence. The UN has been announcing for months that it will soon take part in the fight against the ADF alongside the Congolese army, but a major joint offensive has yet to begin.
But a senior UN source told the BBC that the organisation did not have the capacity to protect all the civilians in the area.
Over the past two decades, numerous armed groups have caused havoc in DR Congo's mineral-rich eastern regions.
The ADF was formed in 1996 by a puritanical Muslim sect in the Ruwenzori mountains of western Uganda.
There are now reports that the group is forming alliances with other rebels in eastern DR Congo.
Peace agreements last year have failed to end violence in the east.