oust the new PARMEHUTU regime from power and establish a socialist republic. Beginning in late 1960 armed groups of Tutsi exiles (called inyenzi or "cockroaches" by the Hutu government) launched attacks into Rwanda from neighbouring countries, with mixed success. The Tutsis in Burundi, supported by that country's newly installed, independent Tutsi republic, caused some disruption in southern Rwanda. The events in Rwanda dramatically worsened Tutsi-Hutu relations in Burundi, and from that point onward the country's Tutsi-led regimes sought to avoid a similar revolution in their own territory. Fear of such a development strongly motivated the Burundian government to massacre thousands of Hutus in 1972 in response to a Hutu uprising, with the participation of some Rwandan Tutsi refugees. Refugees in the Congo, Uganda and Tanzania were less able to organise military operations because of local conditions; exiles in Tanzania were treated well by local authorities and many settled permanently, giving up aspirations to return to Rwanda. The rebel attacks themselves propelled more refugees across the borders, since the government often responded with further attacks on the Tutsi still living in Rwanda. In December 1963 the Burundi-based rebels launched a large-scale surprise attack, seizing Bugesera and advancing to positions near Kigali. The ill-equipped and poorly-organised invaders were easily defeated by the government, whose response to the attack was the largest killing of Tutsi to date: an estimated 10,000 in December 1963 and January 1964, including all Tutsi politicians still in the country. The international community did little in response, and President Kayibanda's domestic power was reinforced. Infighting and the defeat put an end to the Tutsi rebels, who were of no further threat to Rwanda after 1964. Post-revolution Rwanda After the 1963–64 Tutsi massacre and defeat of the Tutsis, Kayibanda and PARMEHUTU ruled Rwanda unchecked for the next decade, overseeing a Hutu hegemony justified by the mantra of "demographic majority and democracy". The regime did not tolerate dissent, ruling in a top-down manner similar to the pre-revolution feudal monarchy and promoting a deeply Catholic, virtuous ethos. By the early 1970s this policy had isolated Rwanda from the rest of the world, and a rebellion began within the Hutu elite. In 1973 senior army commander Juvénal Habyarimana organised a coup, killing Kayibanda and assuming the presidency. In 1990 the Rwandan Patriotic Front (RPF), a rebel group composed primarily of Tutsi refugees, invaded northern Rwanda; this began the Rwandan Civil War. Although neither