The plane carrying passengers crashed into Lake Victoria in Tanzania.

On Sunday, a passenger plane attempting to land in the Tanzanian city of Bukoba on the shores of Lake Victoria experienced a catastrophic crash into the lake, according to the country’s state broadcaster.

The Tanzania Broadcasting Corporation (TBC) reported that 15 people had been rescued, but that it was unclear how many people had been on board the Precision Air flight or whether any had perished.

TBC reported that the plane “fell in Lake Victoria this morning due to storms and heavy rains.” The plane took off from the commercial capital of Dar es Salaam.

Images and video of the plane, which had crashed into Africa’s largest lake, Lake Victoria, went viral on social media, showing the plane almost completely submerged.

TBC also reported that rescue boats had been sent out and that emergency personnel were still working to free any remaining trapped passengers.

Flight 494 from Precision Air, Tanzania’s largest privately owned airline, was “involved in an accident as it was approaching Bukoba Airport,” the airline reported. In its statement, the airline offered no further explanation.

As the rescue effort continued, President Samia Suluhu Hassan of Tanzania urged everyone to remain calm.

She tweeted her sadness at hearing about the Precision Air plane crash. “Let’s remain calm as rescuers continue the rescue operation, asking God to bless us,”