In 1971 Colonel Idi Amin launched a military coup that overthrew the President of Uganda, Milton Obote, precipitating a deterioration of relations with the neighbouring state of Tanzania. Amin installed himself as President and ruled the country under a repressive dictatorship. In October 1978 he launched an invasion of Tanzania. On 1 November he announced the annexation of the Kagera Salient, an 1800 square kilometre (720 square mile) strip of land between the Ugandan border and the Kagera River. Uganda Army troops subsequently pillaged the area they occupied, murdering civilians, stealing cattle, and destroying property, triggering the flight of 40,000 inhabitants southward. Tanzania eventually halted the assault, mobilised anti-Amin opposition groups, and launched a counter-offensive. In January 1979 the Tanzania People's Defence Force (TPDF) seized the Ugandan border town of Mutukula to counter any further threats to Kagera. Though many international actors were sympathetic with the Tanzanian position, numerous African states and the Organisation of African Unity (OAU) strongly encouraged Tanzanian President Julius Nyerere to exercise restraint and not act beyond defending his territory. He had originally not intended to expand the war, but with Amin refusing to renounce his claims to Tanzanian territory and the OAU's criticism of the Kagera invasion being muted, he decided that Tanzanian forces should occupy southern Uganda—specifically the two major towns of Masaka and Mbarara.