(CNN) -- Three United Nations peacekeepers were slain at their military encampment in the volatile eastern Democratic Republic of the Congo Wednesday morning, according to an official with the U.N. mission there.
Seven other peacekeepers were injured -- four of them seriously, said Madnodje Mounoubai, a spokesman for the U.N. peacekeeping mission in the Congo, known as MONUSCO.
"We lost three Indian peacekeepers this morning around 3 a.m. local time in Kirumba camp, in North Kivu Province," Mounoubai said via telephone from Kinshasa, the capital of the Congo.
"About 50 to 60 people were hiding in the bush and then they attacked them. We believe they used spears and knives, but no firearms were used."
He said roughly five people walked up to the entrance of the Indian military battery's camp, making an unknown request. While calling for an interpreter from inside the camp to come and aid them at the gate of the compound, the Indian soldiers were ambushed.
"We don't understand yet why this happened," Mounoubai said.
The spokesman said the injured soldiers were taken to Goma, the provincial capital.
Mounoubai said the area where the Indian peacekeepers were attacked is a haven for various militia groups, including the notorious Mai Mai armed force.
"But we don't know who exactly carried out this attack -- we don't know their identities," he said.
Mounoubai said an investigation was under way.