Electoral violence in Tanzania last year left at least 518 dead, a commission of inquiry organised by the government said on Thursday.

President Samia Suluhu Hassan was declared the winner of the October 29 poll with 98 percent of the vote after key opposition figures were barred from running.

But the election triggered days of protests around the country.

Opposition and religious groups say thousands were killed, with reports of mass graves and bodies being seized from hospital mortuaries.

The government had not given any casualty figures until Thursday, and the commission found that "allegations of the existence of mass graves could not be substantiated".

‘Manipulated images’

"The total number of deaths resulting from the general elections was 518, of whom 490 were male," said Mohamed Chande Othman, head of the commission set up by Hassan, but said that the number was "not final and conclusive".

"The images that widely circulated online, some of them were authentic, while others... had been manipulated, using AI," said Othman.

An internet blackout during and after the vote complicated efforts to confirm the scale of the violence.

The opposition has said the inquiry "cannot be independent or impartial, especially in a situation where the government is the primary suspect in the crimes being investigated".

The violence triggered rare criticism from African observers, with the African Union saying the election did not comply with "standards for democratic elections".