Burundi has banned three United Nations investigators from entering its territory, after the trio presented a report which named officials allegedly involved in last year’s killing and torturing of political opposition. 

The UN Human Rights Council had tasked the team in January with a probe into cases of rights abuses in Burundi, eight months after violence erupted in the country over a controversial decision by President Pierre Nkurunziza to run for a third term. Nkurunziza won the votes in July despite fierce opposition and rampant street demonstrations.

The trio, under a mission known as the United Nations Independent Investigation on Burundi (UNIIB), published their report on September 20. The report investigated alleged human rights violations in the country from April 15, 2015 to June 30, 2016.

According to the findings of the investigators, “gross violations are systematic and patterned and impunity is pervasive,” in the volatile African country during the period. They also warned that “given the country’s history, the danger of the crime of genocide also looms large.”

At least 1,000 deaths, including 564 cases of executions, have been verified during the span of time, the experts said, adding that torture, sexual abuse and arbitrary detention have happened “on a massive scale.”

Burundi has strongly rejected the claims in the report. Last week, the government also dismissed a UN decision to launch a commission of inquiry to identify perpetrators of killings and torture, arguing that it was based on a one-sided report, whose authors have been “politically motivated.”

Nkurunziza’s administration also said the report and its conclusions were based on anonymous and unverifiable sources.

An estimated 300,000 people were killed during a brutal civil war between majority Hutus and minority Tutsis from 1993 until 2006 in Burundi.