About 150 people are feared dead after a boat from the Democratic Republic of Congo sank on Lake Tanganyika on Saturday night.
The captain has reportedly admitted that the boat was carrying twice its official capacity.
Forty-one people survived the tragedy, but a Burundi army spokesman said there was no hope of finding any more.
The M/V Kashowgwe encountered bad weather and capsized off Nyanza-Lac in south-west Burundi, Colonel Augustin Nzabampema told the French news agency, AFP.
"There is no hope of finding the survivors but we have sent a boat to the scene in Burundi to help look for bodies so that they can be buried in dignity," he said.
Burundi sailors counted 111 bodies, he said.
Uvira administrator (mayor) Edouard Madjalibu said that the boat was designed to hold 67 people but the captain, who was among the survivors, said there were up to 130 people on board.
Some witness say there may have been as many as 200 people on board.
A BBC correspondent in Uvira says ferries on Lake Tanganyika are often overcrowded.
Correspondents say that due to the poor infrastructure in war-ravaged DR Congo, ferries are the cheapest and most popular form of transport between lakeside towns.
A delegation from the Congolese Rally for Democracy (RCD-Goma) rebel group which controls eastern DR Congo has gone to Uvira to investigate the situation and to assess how to bury the dead, rebel-controlled radio reports.