Tanzania’s Prime Minister Kassim Majaliwa confirmed Sunday morning that the death toll had risen by three.
Earlier, local authorities said 26 of the 43 people on the Precision Air flight – a Tanzanian airline – were rescued and taken to a hospital.
Flight PW494 had taken off from the coastal city of Dar es Salaam before crashing at 8.53am local time. It was not clear if any of those rescued died in hospital.
Photos showed the plane flying to Bukoba Airport mostly submerged in the lake.
“We managed to save quite a number of people,” Kagera Province Police Commander William Mwampaghale told reporters.
He said: “When the plane was about 100 meters away [328 feet] in mid-air it encountered problems and bad weather. It was raining and the plane crashed into the water.”
Mr Mwampaghale added that rescue efforts were underway.
Tanzanian President Samia Suluhu Hassan has expressed her condolences.
In a tweet, she said, “Let’s continue to remain calm as the rescue operation continues while we ask Allah to help us.”
Want a quick, expert briefing on the biggest news? Listen to our latest podcasts to find out what you need to know…