Human rights chief details violence since President Pierre Nkurunziza said he would seek a third term.
More than 400 people have been killed in conflict in Burundi since April 2015.
The government said it was opposed to meeting with "those who are supporting violence" in the opposition.
Violence has raged in the East African country since President Nkurunziza was re-elected in July.
A Refugees International report found 80 cases of alleged recruitment into a non-state Rwandan militia.
Tensions are high after insurgent attacks last week left roughly 90 dead.
Twelve armed attackers were killed after besieging three military bases in and around Bujumbura.
Ladislas Ntaganzwa is accused of killing and raping thousands of people during the 1994 genocide.
The Public Security Minister and the Deputy Director of the National Police Force are among those facing sanction.
The U.N. Security Council made a unanimous decision on Thursday to pass a resolution condemning the burgeoning crisis in the Easy African nation of Burundi.
Chilling parallels exist between Burundi and Rwanda, where 800,000 died in the 1994 genocide.
Some 240 people have been killed and 200,000 have fled Burundi since April.
Burundi's postponed elections were held Tuesday despite protests at home and abroad.
Godefroid Niyombareh is reportedly staging a coup