PremiumTBC said 15 people had been rescued so far but it was unknown how many passengers were on board the Precision Air plane or whether there were any fatalities.
A passenger plane crashed into Lake Victoria in Tanzania on Sunday while attempting to land at an airport in Bukoba, state-owned Tanzania Broadcasting Corporation (TBC) reported.
TBC said 15 people had been rescued so far but it was unknown how many passengers were on board the Precision Air plane or whether there were any fatalities.
The aircraft, which had departed from the capital, Dar es Salaam, "fell in the Lake Victoria this morning due to storm and heavy rains", TBC reported.
Video footage and images that circulated on social media showed the plane almost fully submerged, with only its green and brown-coloured tail visible above the water line.
Rescue boats were deployed and emergency workers were continuing to rescue other passengers trapped in the plane, TBC added.
Tanzanian President Samia Suluhu Hassan called for calm as the rescue operation continued.
"I have received with sadness the news of the accident involving Precision Air's plane," she tweeted. "Let's be calm at this moment when rescuers are continuing with the rescue mission while praying to God to help us."
Bukoba Airport lies on the shores of Lake Victoria, Africa's largest lake.
Precision Air is Tanzania's largest privately owned airline.
This story has been published from a wire agency feed without modifications to the text.