Protesters have taken to the streets in Tanzania for a third day, defying warnings from the country's army chief to end the unrest.

Demonstrations have been taking place in major cities with young protesters denouncing Wednesday's election as unfair, as key opposition figures were excluded from contesting against President Samia Suluhu Hassan.

An internet shutdown remains in place, making it difficult to confirm reports of deaths, and the authorities have extended a curfew in a bid to quell the protests.

The UN has called on the East African nation's security forces to refrain from using unnecessary or disproportionate force.

We are alarmed by the deaths and injuries that have occurred in the ongoing election-related protests in Tanzania. Reports we have received indicate that at least 10 people were killed, said UN human rights spokesperson Seif Magango, citing credible sources.

Amnesty International in Kenya stated it could not confirm these reports due to communication disruptions in Tanzania.

Hospitals in the country are refusing to give information to journalists or human rights groups regarding casualties. The government has attempted to downplay the violence.

The electoral commission has announced results from more than half of the country's total 100 constituencies. Despite the turmoil, President Samia is expected to win under the ruling Chama Cha Mapinduzi (CCM) party, which has governed since Tanzania's independence in 1961.

On Thursday, army chief Gen Jacob John Mkunda ordered protesters off the streets, asserting that the military would work with other security agencies to control the situation.

The protests have extended to Zanzibar, where opposition has claimed massive fraud in the elections.

Political analysts have noted that President Samia initially gained favor by easing political repression but now faces criticism for escalating government crackdowns on dissent and opposition leaders.