Members of the Ugandan rebel Lord's Resistance Army (LRA) killed 42 civilians with machetes and knives on Thursday morning in a village near the northern town of Kitgum, Ugandan army spokesman Major Shaban Bantariza told IRIN on Friday.
The attackers had killed the most vulnerable people in the village, such as children and the elderly, who were unable to run away, Bantariza said, while numerous others had fled the scene.
"We are encouraging people to go to trading centres or towns where we can protect them," he added. "Those who remain outside in villages are most at risk."
Commenting on what he called "punishment killings", Bantariza said that "Joseph Kony [the LRA leader] is frustrated and desperate".
"He has been trying to abduct people from camps set up for internally displace people and failing. He thinks the local Acholi people should support him and fight for him and that they have betrayed him by not doing so."
The move comes two days after an LRA commander released a group of 18 women and 13 children near Pajule, Pader District, who had been kidnapped years beforehand. Some of them had spent up to 10 years in captivity with the rebels, who had their bases in southern Sudan, Bantariza said.
The Acholi Religious Leaders' Peace Initiative described the women and children as being "in a state of exhaustion", the BBC reported. "They are really destitute. After having walked all this distance from Sudan up here and having been always on the move they are really worn out," said Lam Cosmas, the group's spokesman.
Bantariza said that the "so-called releases" were aimed at giving the impression that the LRA might be changing tactics, in order to attract more members. "The people they released were also unarmed and untrained. He [Kony] kept the ones who can fight for him," he added.