Kinshasa, DR Congo: Congolese national police accused rebels Monday of massacring 39 of their officers in the violence-wracked Kasai region.

The victims were killed in an ‘ambush’ early Friday and buried in a mass grave by supporters of late militia leader Kamwina Nsapu around 75 kilometres north of Tshikapa, in the Democratic Republic of Congo’s central Kasai region, a police spokesman said.

The 39 massacred police officers had been travelling in two army transport trucks ‘with a substantial cargo’ of material and law enforcement equipment, which their attackers hijacked, spokesman Colonel Pierre-Rombaut Mwanamputu added in a statement.

The national police ‘strongly condemns this massacre’ and have taken urgent measures to boost security in that part of the country, the statement said.

The remote region has been plagued by violence since mid-August, when government forces killed Nsapu, a tribal chief and militia leader who had rebelled against President Joseph Kabila’s central government.

Clashes between government forces and Nsapu supporters began in central Kasai, but the violence has since spilled over to the neighbouring provinces of Kasai-Oriental and Lomami, leaving at least 400 people dead.

The Kamwina Nsapu group is accused of numerous atrocities by the United Nations and of using child soldiers.

DR Congo security forces have also faced regular UN condemnation over the use of disproportionate force against the militiamen, who are armed mainly with clubs and catapults.

Earlier this month, seven Congolese soldiers were arrested after the release of a video online implicating troops in an alleged massacre in Kasai-Oriental province.

The accusation of the massacre of 39 officers comes two days before the UN Security Council is due to vote on extending its stabilisation mission in the Democratic Republic of the Congo—the largest UN peacekeeping mission in the world, but with few soldiers in the Kasia region.