Nkurunziza's sour relations with international organisations began in 2015 when he insisted on running for a for a third term.
Later in 2017, Burundi became the first country to withdraw from the International Criminal Court, amid accusations by African countries that the court was targeting Africans for prosecution.
Lewis Mudge, Human Rights Watch director for Central Africa said Nkurunziza betrayed his call.
"When Pierre Nkurunziza was sworn in as president in 2005 at the end of a brutal civil war, many hoped he would lead the country on a path of democratic reforms," Mr Mudge said.
"Nkurunziza was willing to isolate Burundi almost entirely from the international community, with devastating consequences for the Burundian population.