An international human rights group has urged an investigation into Burundi's forces for alleged human rights violations including extra-judicial executions, rape and looting during the deadliest day in the months of unrest over President Pierre Nkurunziza's extended tenure.

Amnesty International regional executive Director Muthoni Wanyeki said Tuesday that the security forces' violent tactics on December 11, in response to an armed attack of three military facilities, represented a dramatic escalation in the scale and intensity of previous operations. She says men were dragged from their homes and shot at close range, while others were shot the instant they opened their doors.

Burundi's government has said its troops acted professionally. Burundi has been hit by deadly unrest since April when Nkurunziza ran and won re-election to a third term in office.