In 1971 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.

[5][4] Having escaped from Kampala, he traveled to a succession of cities in eastern and northern Uganda, urging his remaining forces "to go back and fight the enemy who had invaded our country", even as he prepared to flee into exile.

[6][7] Most Uganda Army units opted to surrender, desert or defect to the Tanzanian-led forces,[6] but some decided to continue to fight for Amin's defunct regime.

[10] The bridge, which lay 60 kilometres (37 mi) south of Gulu, was one of three such crossings over the Nile in Uganda,[11] and it had been frequently used by Amin's agents to dump the bodies of executed dissidents into the river.

[12] Anti-Amin militants of Yoweri Museveni's Front for National Salvation were originally supposed to seize the location before Kampala fell, but moved too slowly.

[6] A group of Uganda Army soldiers maintained a roadblock at the Karuma Falls Bridge, where they harassed and robbed passing civilians.

[13] The 205th Brigade's advance was delayed due to a gasoline shortage, and by the time the requisite fuel had arrived in Masindi, the unit was two days behind schedule.

The evening before the brigade was to cross the river, a reconnaissance team spotted a company of Uganda Army soldiers at the bridge.

A Tanzanian battalion led by Lieutenant Colonel Ahmed Mazora charged across the bridge under the cover of their own artillery, which summarily eliminated the Ugandan mortar team.

[11] Tanzanian Lieutenant Colonel Steven Isaac Mtemihonda stated that his comrades "counted more than eight dead bodies" in the Ugandans' former positions.

[18] The Tanzanian arrival coincided with widespread mob violence, as Acholi civilians attacked members of ethnic groups associated with Amin's government.