Nine lions at the world famous Serengeti National Park have been poisoned, Tanzania National Parks spokesman Pascal Shelutete Said.
Wildlife officials discovered the carcasses of the lions over the weekend, media reports say.
The motive for the poisoning is unclear.
Seven lions were killed in a similar manner in the park in 2015.
In neighbouring Uganda, 11 lions were found dead from suspected poisoning at the Queen Elizabeth National Park in April.