At least 890 people are believed to have been killed in ethnic violence in northwestern Democratic Republic of Congo last month, the United Nations human rights office said on Wednesday.

The toll doubles an estimate provided on Monday by a local priest and a civil society activist who said that at least 400 people had been killed in bloodshed which led the government to cancel voting there in last month’s presidential election.

“According to allegations from credible sources, at least 890 people were killed between 16 and 18 December in four villages in Yumbi territory, Mai-Ndombe province in the west of the Democratic Republic of the Congo, in what appear to have been clashes between the Banunu and Batende communities,” the UN human rights office said in a statement.