International human rights organization Amnesty International on Friday released satellite images and video footage showing five possible mass graves in areas near Burundi's capital Bujumbura.

The global rights body, in a report containing witness accounts, claimed that the Burundian security forces allegedly killed dozens of people in December of last year and dumped their bodies in mass graves in the Buringa area on the outskirts of Bujumbura, according to The Independent.

"These images suggest a deliberate effort by the authorities to cover up the extent of the killings by their security forces and to prevent the full truth from coming out," Muthoni Wanyeki, Amnesty International's regional director for East Africa, the Horn and the Great Lakes, said in a statement. Read the complete report here.

"Families need to know what happened to their loved ones and to be able to bury them in dignity. These suspected grave sites must be secured until proper investigations can be carried out, and any bodies found in them should be exhumed to assess the causes of death," he added.

Amnesty International's shocking revelation comes days before an African Union summit on the Burundian crisis.

"African leaders gathering at the AU summit must call on the Burundian government to grant international investigators access to all suspected grave sites and launch an immediate, independent and impartial investigation into the killings and why most families were given no opportunity to retrieve and bury their dead," Wanyeki said.

Nearly 450 people have been killed and tens of thousands have fled their homes in violence that erupted after President Pierre Nkurunziza decided to run for a controversial third term earlier this year, according to Africa News. He eventually won the third term.