GENEVA — A group of independent experts called Tuesday 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 as the president sought to stay in power.

The three experts commissioned by the U.N. human rights office recommended the establishment of a commission of inquiry after examining abuses over 14 months through June 30. They said the pattern of abuses suggests they have been deliberate and that Burundi’s government has the power to stop them.

Violence soared after Nkurunziza’s contested decision last year to seek a third term in office, which critics called unconstitutional. At least 500 people have died in the East African country since April 2015.

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

They also noted cases of assassinations, sexual violence, disappearances and torture, including the “attachment of weights to victims’ testicles, the crushing of fingers and toes with pliers, progressive burning with a blowtorch and being forced to sit in acid or on broken glass or nails.”

Their final report also asked the U.N. Human Rights Council to consider expelling Burundi as one of its 47 members if the situation doesn’t improve.

The experts called on “the United Nations, particularly the Security Council, to discharge effectively its mandate to ensure peace and security, and to protect . the civilian population from threat of physical violence, under chapter VII of the United Nations Charter.”

Chapter 7 can be enforced militarily.

More than 260,000 people have fled Burundi during the unrest.

Burundi’s government has rejected international efforts to send U.N. police to monitor human rights abuses or African Union peacekeepers to help calm tensions.