UN mission MONUSCO spokesman said a "rapid intervention force" of peacekeepers was dispatched to the area in the morning.
Nineteen people were killed on Wednesday in eastern Democratic Republic of Congo by a suspected group blamed for massacres that have sparked deadly protests against the United Nations' peacekeeping mission, the UN said.
Local administrator Donat Kibwana said 14 bodies had arrived at the morgue in Oicha, 30 kilometres (18 miles) from the city of Beni, adding that they were killed by machete.
A spokesman for the UN mission MONUSCO confirmed this figure, but later said the toll had "been revised upwards. Nineteen dead."
"The army is already at the site and is pursuing" the attackers, Kibwana said by phone from Oicha, while the MONUSCO spokesman said a "rapid intervention force" of peacekeepers was dispatched to the area in the morning.
The not-for-profit Congo Research Group (CRG) said the new massacre brought to 99 the number of civilians killed by armed groups in the Beni area since November 5, following the launch of an offensive by the country's army.
The attack in Oicha, about 30 kilometres from Beni, took place overnight, said Kibwana. He blamed the Uganda-based Allied Democratic Forces (ADF) rebels, who have killed more than 1,500 people in and around Beni in the past four years.
"We have reinforced the military presence in the territory of Beni, but also the army has pursued the rebels," he said. "We call on the population to remain calm."
This comes shortly after the UN peacekeeping mission in the country said it was launching a probe after gathering evidence that its troops may have killed a young demonstrator following a protest in the east of the country.
"The elements that we have indicate that it was Blue Helmets who were responsible for the death of this young man," said a spokesman for the mission, MONUSCO.
The first death occurred on Tuesday in the northeastern city of Beni, where angry locals have been demonstrating against MONUSCO, accusing it of failing to protect them against a notorious militia.
In a statement, MONUSCO quoted mission chief Leila Zerrougui as saying the man "was reportedly killed in an exchange with Blue Helmets as he was about to throw a petrol bomb."
TRT World spoke with David Masomo, director of NGO Mavuno, for more on the security situation in Beni.
Separately, a student was injured and 10 others arrested on Wednesday as DRC police broke up a demonstration outside the university in Goma, one of two cities in the province of North Kivu where anger has boiled over.
Dozens of civilians in and around the town of Beni have been killed by a shadowy group, the ADF since DRC's army launched an offensive against it on October 30.
The mounting toll has led people to take to the streets, accusing the authorities and MONUSCO of inaction.
On Monday, a crowd stormed one of the two UN camps near Beni and set fire to one of its offices.
Six people have been killed in the protests since Monday.
"Our demonstration is patriotic. MONUSCO is standing on the sidelines as the massacres unfold when its chief mission is to protect civilians," said one of the demonstrators in Wednesday's protest, law student Fiston Muhindo.
"They have to go. MONUSCO is serving no purpose," said fellow law student Junior Mastaki, adding that authorities were "incapable" of protecting the public.
TRT World spoke with Congolese activist Vava Tampa, who said killings in DRC have been taking place for several years "under the nose of" the UN peacekeepers.
CRG said the ADF — a group of Ugandan origin that has plagued the eastern DRC since the mid-1990s — has killed more than a thousand civilians since October 2014.
MONUSCO, one of the biggest UN peacekeeping operations in the world, today comprises more than 16,500 military personnel and observers, 1,300 police and at least 4,000 civilians.
But it has struggled to make headway in a vast country beset by armed groups as well as entrenched poverty and poor governance.
Responding to criticism of inaction, it has pointed out that troops are unable to deploy in combat without the approval of the host country and in coordination with national forces.
On Monday, DRC's armed forces said that they had taken "all of (ADF's) strongholds and headquarters" in the forests around Beni.
The same day, the president's office announced the DRC and UN peacekeepers would launch "joint operations" to beef up security in Beni, and the army would establish an "advance headquarters" in the town.
Meanwhile, the World Health Organization said it evacuated 49 of its staff working on the Ebola epidemic in the country. It blamed the worsening security situation in the Beni region.
TRT World 's Sharon Ogunleye has more.