The death toll from a crowded ferry capsizing in Lake Victoria rose sharply to 207 on Saturday, a Tanzanian minister said, as rescue workers found a lucky survivor.
Public radio quoted the transport minister as updating the number of dead from 170 earlier in the day.
Mr Joseph Mkundi, a lawmaker for the Ukerewe district, told AFP there were 41 known survivors among the passengers of the mv Nyerere — a ferry built to carry 100 people, according to state media.
It capsized on Thursday close to the pier on Ukara Island. Although hopes were fading of finding any more survivors by day three of the search effort, workers rescued an engineer who had managed to locate a pocket of air in the vessel.
According to Mr Mkundi, the engineer had shut himself inside a "special room".
Tanzanian President John Magufuli ordered the arrest of ferry management. Witnesses told AFP the ferry sank when passengers rushed to one side to disembark as it approached the dock. Others blamed the captain, saying he had made a brusque manoeuvre.
In a speech broadcast on TBC 1 public television, Mr Magufuli said "it appears clear that the ferry was overloaded". He added: "Negligence has cost us so many lives ... children, mothers, students, old people.
"I ordered the arrest of all those involved in the management of the ferry. The arrests have already begun," he added.
The President declared four days of national mourning and said the government would cover the funeral expenses of the victims.
State television cited witnesses reporting that more than 200 people had boarded the ferry at Bugolora, a town on the larger Ukerewe Island. It was market day, which usually sees the vessel packed with people and goods.
"I have not heard from either my father or my younger brother who were on the ferry. They had gone to the market in Bugolora to buy school uniform and other supplies for the new school term," Domina Maua, among those seeking information about loved ones, said.
Mr Sebastian John, a teacher, said such tragedies had become part of life for those living on the lake.
"Since my birth, people have gone to their deaths on this lake, but what are we to do? We did not choose to be born here, we have nowhere to go," he said.
Tanzania's Electrical, Mechanical and Services Agency, which is responsible for ferry services, said it was unknown how many passengers were aboard mv Nyerere.
The ageing vessel, whose hull and propellers were all that remained visible after it overturned, was also carrying cargo, including sacks of maize, bananas and cement, when it capsized about 50 metres from Ukara dock.
The cause of the accident was not immediately clear, but overloading is frequently to blame for such incidents.
The country's opposition has accused the government of "negligence". "We have often raised concerns about the poor condition of this ferry, but the government turned a deaf ear," Mr John Mnyika, deputy secretary-general of Chadema, the main opposition party, said.
Russian President Vladimir Putin and the leaders of Uganda and Kenya offered their condolences, while Pope Francis, in a statement, expressed "the greatest solidarity with those who have been bereaved".