The Ugandan army on Sunday accused Lord's Resistance Army (LRA) rebels of hacking to death 45 people in a church in northeastern Democratic Republic of Congo.
An aid official confirmed Friday's massacre, saying the killings took place in a Catholic church in the Doruma area, around 40 kilometers from the Sudanese border.
"There are body parts everywhere. Inside the church, the entrance and in the church compound," the aid official said.
"We got information the rebels cut 45 people into pieces," added army spokesman Captain Chris Magezi.
"They were cut with pangas (machetes) and hit with clubs but some luckily managed to escape. Our forces came to know about the killings while pursuing the LRA yesterday (Saturday) and the pursuit is on for the killers."
Magezi said the victims, mostly women, children and the elderly, were mutilated in the style used by Hutu extremists during the 1994 Rwanda genocide.
Magezi later said 13 of the insurgents were shot dead by the forces.
"We came in contact with the group that killed the civilians in the church near Doruma. We put 13 of them out action and we recovered from them nine sub-machine guns," he said. "We are pursuing the rest of the group."
Forces from Uganda, Democratic Republic of Congo and south Sudan launched a joint operation against the Ugandan LRA rebels in northeastern DR Congo earlier this month.
The vice-governor of Orientale province, Joseph Bangakya Angaze, said by telephone that "fighting has broken out around Doruma since Friday, between elements of the LRA and local groups" set up to defend their communities.
Magezi had also accused the rebels of killing 35 civilians in attacks on Wednesday and Thursday in areas in south Sudan and northeastern Congo.
But LRA spokesman David Nyekorach Matsanga denied the rebels were behind any of the killings.
"Reports about the LRA killing innocent civilians is another propaganda campaign by the Uganda army," Matsanga said.
"I am not a military spokesman for the LRA but I have it on good authority from the field commanders that the LRA is not in those areas where the killings are reported to have taken place.
"We need an independent verification to know who is responsible for these killings in Doruma because LRA has stated before we want peace not war because fighting won't help," he said.
The two sides have been engaged in peace talks led by the government of South Sudan for more than two years.
On Saturday, Matsanga said the LRA chief Joseph Kony was still open to talks but preferred Tanzanian or South African mediation because south Sudan was involved in the military offensive.
Kony has repeatedly refused to sign a peace deal with Kampala because of International Criminal Court arrest warrants against him and his lieutenants for war crimes.
But Magezi insisted the killings of civilians will not deter the joint forces from hunting the rebels. He also condemned "these heinous acts by the LRA terrorists."
"They (LRA) think by killing innocent civilians the allied forces will be intimidated to back off from the operation. They are misleading themselves," said Magezi, who is also the spokesman of the regional forces.
"We will continue to pursue them and they will pay with their blood."
Uganda has already signed the final peace agreement concluded in April to end the civil conflict that has ravaged the country's northern region.
Kony's rebels are accused of having raped and mutilated civilians, forcibly enlisting child soldiers and of massacring thousands during two decades of conflict.
Kony, a semi-literate former altar boy, took charge in 1988 of a regional rebellion among northern Uganda's ethnic Acholi minority.© Wire reports