The Ikiza (variously translated from Kirundi as the Catastrophe, the Great Calamity, and the Scourge), or the Ubwicanyi (Killings), was a series of mass killings—often characterised as a genocide—which were committed in Burundi in 1972 by the Tutsi-dominated army and government, primarily against educated and elite Hutus who lived in the country.

[9] By 1965, assassinations, subversive plots, and an attempted coup had generated the murder of numerous Hutu members of Parliament and sparked ethnic violence in rural areas.

Some European diplomats believed Micombero had legitimately agreed to let Ntare return unmolested "in a moment of mental aberration" only to quickly regret his decision and "over-react" by arresting him.

Burundi was home to thousands of Zairean exiles who were culturally distinct from other members of Burundian society but had grievances against the Groupe de Bururi and were receptive to the incitement against Micombero's regime.

In reality, the Zairean rebels who fought alongside the Hutu militants were mostly the former followers of Gaston Soumialot, who had led a similar rebellion in eastern Zaire during the same time period.

[27] Despite these ethnic killings, researcher Nigel Watt argued that the insurgents initially hoped to gain the support of Tutsi monarchists who were upset over Ntare's arrest.

[31] Historians Jean-Pierre Chrétien and Jean-François Dupaquier, after evaluating several witness testimonies, concluded that Ntare was shot and stabbed to death by a group of about a dozen soldiers led by Captain Ntabiraho on the orders of Micombero at about 23:15.

[33][20] State media also announced the installation of military governors to replace civilians in every province, revealed Ntare's death, and claimed that monarchists had assaulted his palace in Gitega in an attempt to free him and that he "was killed during the attack".

President Mobutu Sese Seko responded by dispatching a company of Zairian paratroopers to Bujumbura, where they occupied the airport and guarded strategic locations around the city.

Commandant Martin Ndayahoze, a Hutu officer and former government minister who had been loyal to Micombero, disappeared after being summoned to a crisis meeting[43] early in the morning on 30 April.

[58] A handful of foreign Christian priests in northern Burundi condemned the repression, resulting in police interrogating them for engaging in "political activity" and placing them under surveillance.

[60] Several Catholic mission superiors penned a letter to the Burundi Episcopate which attacked church officials for failing to condemn the atrocities committed against Hutus.

The categories Ntavyo delineated were as follows: civil servants, who used their positions in government to deliberately undermine state institutions; church officials, who preached social division and fanaticism; and wealthy merchants, who used their money to persuade others to support their ulterior motives.

[114] United States officials at their embassy in Bujumbura were quick to notice the repression, as trucks full of bodies passed their building and their Hutu employees spoke about relatives being murdered.

[119] Officials at the United States embassy in Nairobi, Kenya initially shared details of the situation in Burundi with American reporters, but this stopped after Melady criticised them for divulging the information.

[124] The Belgians also threatened to suspend its annual $4.5 million aid contribution to Burundi but this was never carried out, as policy makers took the position that withdrawing assistance would be more harmful to the Burundian people than the government.

During this time the American, Belgian, French, West German, Rwandan, and Zairean diplomats held several meetings at the Apostolic nunciature in Bujumbura where they expressed their feelings that the Burundian government's repression was no longer related to suppressing the uprising but had extended into a campaign of ethnic revenge.

[143] The State Department arranged for diplomat David D. Newsom to meet Burundian Ambassador Terence Tsanze on 18 October to explain that the actions were meant to protest the anti-Hutu violence.

Tsanze responded defensively, arguing that the Hutu uprising had posed the greatest threat to Micombero's government to date, denying that ethnicity was a major factor in the reprisals, and maintaining that all foreign aid was equitably distributed.

[160] Policy analyst David Rieff wrote that the targeting of Hutus based on education status meant that the killings qualified under international law as genocide.

[40] While most academic discussions about the use of the term genocide in relation to the 1972 events in Burundi involve the mass killing of Hutus by Tutsis, Chretien and historian Jean-François Dupaquier considered the anti-Tutsi activities of the Hutu rebels as evidence of a projet génocidaire which never came to fruition.

No original copies of these documents are known to exist, though the two historians cited a book by Marc Manirakiza, an opponent of Micombero's regime who claimed to have reproduced these tracts in their near entirety in his work.

Lemarchand rejected the historical authenticity of the documents[101] and criticised Chretien's and Dupaquier's hypothesis as "uncritically endorsing the official version of the Burundi authorities at the time" and not supported by empirical data.

Some authors attribute the obedience of the Hutus to resignation in the face of overwhelming obstacles, while others suggested that their actions were rooted in Burundi's feudal history and a culture of Hutu subservience to Tutsis.

[172] The Ikiza triggered a new wave of thinking among the Hutu refugees, whereupon they came to believe that the Tutsis' ultimate goal was to kill enough Hutus to change the demography of Burundi so that both ethnic groups would be about equal in number, thus strengthening their political influence.

[177] Tanzanian political leaders sought to maintain good relations with Burundi, and openly discouraged attempts by the refugees to sponsor subversion in their home country.

[188] Meanwhile, the Carnegie Endowment for International Peace published a report on the genocide, advocating that the United States use its position as the chief purchaser of Burundian coffee to apply economic pressure to Micombero's regime.

His government's use of vigilante committees to implement the programme generated instability when the bodies began questioning the power of the authorities, facilitating army officer Juvénal Habyarimana's coup in 1973.

[202] Burundian Hutus have retrospectively cited the existence of a "Simbananiye plan", a plot devised by the former foreign minister in 1967 before the Ikiza to eliminate the monarch and the Hutu elite,[91] thus demonstrating the regime's alleged genocidal intent.

[202] In 2014 the Parliament of Burundi passed a law calling for the establishment of a Truth and Reconciliation Commission (CVR) to investigate atrocities and repression in the country between 1962 and 2008,[206] including the Ikiza.