Tanzanian police have warned against the use of social media to spread misinformation following a widely shared video of an alleged military officer criticising the government, three weeks ahead of general elections.

Identifying himself as "Capt Tesha" from the air force, he accuses the government of corruption, rights violations and political interference in the military.

The military did not respond to BBC inquiries about his identity, and the BBC has not been able to verify whether he is a serving officer.

The purported officer urges military chief Jacob Mkunda to take action and ensure the country is united, and to uphold citizens' rights.

He also encourages Tanzanians to push for their rights and hold demonstrations, saying the security forces are behind them.

"We cannot let the nation be lost in the hands of a few people. I also advise my chief of defence to take action against what is happening in the country," he says.

It comes as Tanzania is preparing to hold general elections amid a tense environment.

In an apparent response to the viral video, the military has warned against attempts to draw it into politics.

Military spokesman Col Bernard Masala Mlunga said such information was being posted by individuals "claiming military affiliation or are former members dismissed for misconduct or political activism".

"The TPDF [Tanzania People's Defence Force] continues to carry out its constitutional duties with integrity, loyalty, and professionalism, in full accordance with the [Tanzanian] laws," he said in a statement.

On Sunday, the police warned that sharing of "criminal and inflammatory" information was a misuse of social media driven by ill intentions.

"The [police force] assures Tanzanians that it will continue to hunt for [those sharing such content], arrest them and bring them to justice," it said in a statement.

Tanzanian opposition activists have been re-sharing the viral video on social media, interpreting it as a sign of military solidarity with them.

President Samia Suluhu Hassan is seeking to retain the presidency under the ruling Chama Cha Mapinduzi (CCM) in the forthcoming elections.

The main opposition party, Chadema, has been banned from participating in the polls, and its leader Tundu Lissu has been detained since April.

He faces treason charges, and a hearing was due to start on Monday. Human rights groups say the charges are politically motivated and meant to silence him.

Critics of the government have also been targeted in recent months and there are growing concerns about whether the 29 October elections will be free and fair.

Many civil society groups, journalists, and political observers say the government has tightened control over the media, public gatherings and opposition activities.