KINSHASA, Congo (AP) — More than 3,300 people have been killed in the volatile Kasai provinces of central Congo since August, according to a document released Tuesday by the Catholic church, as the U.N. called for an international investigation.

The new death toll came as the U.N. human rights chief called for an independent, international probe into hundreds of recent killings there, faulting the government for failing to protect civilians.

Zeid Ra'ad al-Hussein cited "harrowing" reports from U.N. rights experts he deployed this month to interview refugees from the central Kasai provinces.

"My team saw children as young as 2 whose limbs had been chopped off; many babies had machete wounds and severe burns," he said in his report to the U.N. Human Rights Council. "One 2-month-old baby seen by my team had been hit by two bullets four hours after birth; the mother was also wounded. At least two pregnant women were sliced open and their fetuses mutilated."

The government will soon publish its own report on the crisis, Congolese government spokesman Lambert Mende told The Associated Press Tuesday.

"Beyond verifying whether these figures are true or not, it demonstrates that this is a real security situation that must absolutely lead to an appropriate government reaction to put an end to this," he said.

The region in central Congo exploded into violence after a traditional chief known as Kamwina Nsapu was killed in a military operation in August 2016 after his militants had revolted against Congolese authorities.

The subsequent fighting had previously been blamed for 400 deaths before the Catholic church released the figure of 3,300 on Tuesday. Among the victims were two foreign U.N. experts — American Michael Sharp and Zaida Catalan, a Swedish-Chilean national.

Militants loyal to Nsapu filmed themselves killing the two, who had been investigating allegations of human rights abuses in the area. Their bodies were later found in a shallow grave along with the body of their Congolese colleague.

Associated Press writer Jamey Keaten in Geneva contributed.