Tanzanians are voting today in a general election, amid reports of internet shutdown and the refusal of government to accredit thousands of election monitors.
In addition was the arrest of an opposition leader, Maalim Seif Sharif, in the semi-autonomous islands of Zanzibar.
Sharif is the leader of Zanzibar’s main opposition party ACT Wazalendo.
Voters have until 16:00 local time (13:00 GMT) to cast their ballot. Results are expected to be announced within one week.
Tanzanians began complaining about a blocked internet since Monday.
On Twitter, Tanzanians complained that they could not access social networks like WhatsApp and using certain keywords are restricted on SMS.
Twitter weighed in on the problems on Tuesday, confirming it was “seeing some blocking and throttling” of its services ahead of today’s polls.
It appealed for the respect of “basic human rights”.
“Internet shutdowns are hugely harmful, and violate basic human rights and the principles of the #OpenInternet #KeepItOn”, Twitter said in a tweet.
In the election, President John Magufuli, whose Chama Cha Mapenduzi (CCM) party has ruled Tanzania since independence in 1961, is seeking a second term in office.
His main challenger is Tundu Lissu of the biggest opposition party, Chadema, who survived an assassination attempt three years ago.
He returned from Belgium in July where he had undergone rounds of treatment for gunshot wounds.
The BBC reports that 15 candidates are running for president.
Apart from Magufuli and Lissu, there are 13 other candidates running for the presidency.
Among them is former foreign minister Bernard Membe, an ex-colleague-turned-critic of Mr Magufuli who defected from the ruling party and now leads ACT Wazalendo.
Under Tanzania’s electoral rules, the winning candidate requires a simple majority to become president.
Some 29.1 million people are registered to vote in today’s general election – six million more than than the previous polls in 2015.
They include residents of Zanzibar who vote for the islands’ leaders – including the election of a Zanzibari president – as well as in Tanzania’s national election.