A group of independent experts is calling for the creation of an U.N. panel to deepen a probe of "gross human rights violations" in Burundi, pinning most of the blame on President Pierre Nkurunziza's government and its allies.

The three experts commissioned by the U.N. human rights office recommend the establishment of a commission of inquiry after examining abuses over 14 months through June 30.

Violence soared after Nkurunziza's contested decision last year to seek a third term in office.

Abuses include 564 executions since April 26 last year, which the experts call a "conservative estimate" from the U.N. rights office.

Their final report released Tuesday asks the U.N. Human Rights Council to consider expelling Burundi as one of its 47 members if the situation doesn't improve.