Tanzania’s main opposition party claims around 700 people have been killed in three days of election protests, with protesters still on the streets in the midst of an internet blackout.

The authorities have not responded to the claims and foreign journalists were largely banned from covering the election, making it difficult to verify the details.

President Samia Suluhu Hassan went to the election with a clear advantage after her main challengers were either jailed or barred from standing.

But the election descended into chaos as huge crowds took to the streets of Dar es Salaam and other cities, tearing down her posters and attacking police and polling stations, leading to an internet shutdown and curfew.

The United Nations on Friday urged Tanzania's security forces to refrain from using unnecessary force against demonstrators and demanded investigations into election-related violence.

Police and army deployed

The opposition Chadema party told AFP on Friday that "around 700" people had been killed in three days of election protests.

A party spokesman said protesters marching on the city centre in Dar es Salaam on Friday were met by a heavy police and army presence.

"As we speak the figure for deaths in Dar (es Salaam) is around 350 and for Mwanza it is 200-plus. Added to figures from other places around the country, the overall figure is around 700," Chadema spokesman John Kitoka told AFP.

"The death toll could be much higher," he warned, saying killings could be happening during the nighttime curfew.

UN alarmed by deaths

The UN human rights office also said it had received credible reports of deaths in the economic capital Dar es Salaam, in Shinyanga in the northwest, and Morogoro in the east, with security forces firing live ammunition and tear gas to disperse protesters.

"We are alarmed by the deaths and injuries that have occurred in the ongoing election-related protests in Tanzania," office spokesman Seif Magango told reporters in Geneva, speaking from Nairobi.

"We call on the security forces to refrain from using unnecessary or disproportionate force, including lethal weapons, against protesters, and to make every effort to deescalate tensions. Protesters should demonstrate peacefully."

Magango said the internet appeared to have been widely restricted since Wednesday, without any official reasons being given.

He said the Tanzanian authorities should promptly reinstate access "and facilitate citizens' full enjoyment of their rights to freedom of expression, association and peaceful assembly".

"Curtailment of communication will only further undermine public trust in the electoral process," he added.

The spokesman said the electoral campaigns had been "marred" by allegations of arbitrary arrests and detentions of opposition figures, including the opposition Chadema party leader Tundu Lissu, and reported enforced disappearances of people expressing dissenting views.

‘Investigate violence’

"All those in arbitrary detention must be immediately and unconditionally released and those held legally must be accorded full due process and fair trial rights," said Magango.

"We urge the authorities to ensure prompt, impartial and effective investigations into all cases of election-related violence, and to ensure those responsible are brought to justice."

In Zanzibar, a tourist hotspot, Hassan's ruling party had already been declared winner of the local vote on Thursday.

The opposition party, ACT-Wazalendo, rejected the result, saying: "They have robbed the people of Zanzibar of their voice... The only solution to deliver justice is through a fresh election."

The ruling party (Chama Cha Mapinduzi: CCM) was due to give a press conference later in the day.