KINSHASA, Congo — More than 3,300 people have been killed in central Congo’s volatile Kasai provinces since August, according to a document released Tuesday by the Catholic church, as the United Nations called for an international investigation after accounts of atrocities against civilians.

The death toll was reported as the UN human rights chief faulted the government for failing to protect civilians, citing ‘‘harrowing’’ reports from UN rights experts deployed this month to interview people displaced by the fighting between government forces and militia members.

‘‘My team saw children as young as 2 whose limbs had been chopped off; many babies had machete wounds and severe burns,’’ Zeid Ra’ad al-Hussein said in his report to the UN Human Rights Council.

Among the victims were two foreign UN experts — Michael Sharp of the United States and Zaida Catalan, a Swedish-Chilean national.

The region in central Congo exploded into violence after a traditional chief known as Kamwina Nsapu was killed in a military operation in August after his militants revolted against Congolese authorities.

Associated Press