President Samia Suluhu Hassan had sought to solidify her position and silence criticism within her party in the virtually uncontested polls, with the main challengers either jailed or disqualified.
In the run-up, rights groups condemned a “wave of terror” in the east African nation, which has seen a string of high-profile abductions that ramped up in the final days.
A heavy security presence on Wednesday failed to deter hundreds protesting in economic hub Dar es Salaam and elsewhere, some singing: “We want our country back.”
Unverified images on social media showed initially small protests escalated during the day with reports of police responding with live fire as they targeted polling stations, police vehicles and businesses connected to the ruling party.
A diplomatic source said the unrest continued into the night despite a curfew imposed by police.
An Internet blackout was still in place on Thursday, while the police and army had set up checkpoints around Dar es Salaam and other cities, the diplomatic source said.
Schools and colleges were closed on Thursday and civil servants told to work from home, an AFP reporter said.
The government has remained silent and the heavily controlled local media made no mention of the unrest, nor provide any update on the election.
There are reports that upwards of 30 people may been killed in Wednesday’s violence, the diplomatic source said, but this could not be verified.
“It’s unprecedented… Where we go from here is unclear,” they said, with Hassan’s status “uncertain”.
Unrest was reported in multiple areas, including Songwe in the west and tourist hub Arusha.
Foreign journalists have been largely banned from travelling to mainland Tanzania to cover the elections.
‘Deeply disturbing’
Much of the anger online has been directed at Hassan’s son, Abdul, who has been in charge of an “informal task force” of police and intelligence services to manage election security, according to specialist publication Africa Intelligence.
It is blamed for a massive increase in abductions of government critics in the last days before the vote, including a popular social media influencer, Niffer, who was accused of promoting protests with jokey videos about selling face masks.
Hassan has faced opposition from parts of the army and allies of her iron-fisted predecessor, John Magufuli, since coming to power, analysts say.
Amnesty International said late Wednesday they had documented “two reported deaths” from social media images and videos.
They labelled the violence “deeply disturbing”, warning the “risk of further escalation is high” as they urged restraint from authorities.
A member of opposition party Chadema indicated that they had reports of at least four deaths, but stressed they were “not certain” of the figures.
Hassan came to power in 2021, elevated from vice-president on the sudden death of Magufuli.
She faced internal opposition as the country’s first female leader but was feted by rights groups for easing restrictions on the opposition and media.
Those hopes faded as she oversaw a crackdown described by Amnesty as a “wave of terror” including “enforced disappearance and torture… and extrajudicial killings of opposition figures and activists”.
Her main challenger, Tundu Lissu, is on trial for treason, facing a potential death penalty and his party, Chadema, banned from running.
The only other serious candidate, Luhaga Mpina of ACT-Wazalendo, was disqualified on technicalities.
