AT LEAST 136 bodies have been recovered from Tanzania’s Lake Victoria after a ferry capsized, with worries high that the death toll will rise, President John Magufuli has told a local newspaper.

He also told the Citizen that the captain of a ferry has been arrested and that there is reason to believe the captain was not even on board at the time of the accident, having left control of the ship to an inexperienced crew member. The president also ordered further arrests of those responsible for the accident, so they can be questioned.

It “is obvious more bodies are trapped in the capsized vessels,” he told the newspaper, noting that the MW Nyerere was likely carrying far more than the 25 tons of cargo for which it was certified.

About 100 people were rescued after the packed ferry, the MW Nyerere, capsized on Thursday afternoon, regional commissioner John Mongella said. Initial estimates showed that the ferry was carrying more than 300 people between Bugolora and Ukara Island, but the exact number of passengers remains unknown.

Expert divers had arrived on the scene from different parts of the country on Friday morning to speed up rescue operations, according to Mongella. The vessel sank only several metres from the dock near Ukara Island in Ukerewe district, according to Temesa, the company that maintains the country’s ferries. The ferry capsized, trapping many of the passengers inside.

The reason for the disaster was still under investigation on Friday. Magufuli announced three days of mourning following the accident. Pope Francis also said he was “saddened” by the accident.

“His Holiness Pope Francis expresses his heartfelt solidarity with those who mourn the loss of their loved ones and who fear for the lives of those still missing,” the Vatican said in a statement.

UN General Secretary Antonio Guterres sent his condolences to the victims’ relatives, the government and the citizens of Tanzania, adding that the United Nations stands in solidarity with the country at this difficult time and would be ready to help if necessary, Guterres’ spokesman Stephan Dujarric said. German Chancellor Angela Merkel wrote Magafuli, saying:

“I would like to express to you and to the citizens of Tanzania my sincere condolences and my deepest sympathy.” Accidents are not uncommon on Lake Victoria, which straddles Tanzania, Uganda and Kenya, as well as on the Indian Ocean, which borders Tanzania. Poor maintenance and overloading is often the cause of accidents.

In 2011, 192 people were killed when a heavily overloaded ferry capsized between the country’s most populous city, Dar es Salaam, and the tourist island of Unguja (referred to informally as Zanzibar).

A year later, more than 70 people died when another ferry sank near Chumbe Island, an islet near Zanzibar.