Fresh protests have broken out in Tanzania's major cities, a day after elections marred by clashes between opposition supporters and the police.

Gunfire was heard in the northern city of Mwanza, while clashes broke out in the capital Dodoma and the main city Dar es Salaam, which is under heavy security with major roads blocked.

Protesters accuse the government of undermining democracy, as the main opposition leader is in jail and another opposition figure was disqualified from the presidential election, bolstering President Samia Suluhu Hassan's chances of winning.

The electoral commission has started announcing results, with Samia getting nearly 95% of the vote in south-western Mbea province.

She has also taken the lead in several other constituencies on the mainland and in Zanzibar.

EU lawmakers call the election a "fraud" that has been "unfolding for months", and say it was neither free nor fair.

Kenya has warned its citizens not to join protests at the border town of Namanga, where one person is feared to have been killed in clashes.

Hundreds of Tanzanians crossed into Kenyan territory, barricading roads, lighting bonfires, and tearing down posters of President Samia.

Trucks transporting goods were stuck at the border.

The US Embassy in Tanzania reported that the road to Dar es Salaam's international airport was among several major routes that remained closed on Thursday.

An eyewitness told the BBC that he saw hundreds of protesters pouring into Mwanza city, which lies on the shores of Lake Victoria and has the biggest population after Dar es Salaam. 

"After barely 10 minutes, we started hearing gunfire and tear gas explosions," he said. 

"We see some injured people are being evacuated towards our way." 

The government has ordered civil servants to work from home until Friday as tensions escalate.

Rights group Amnesty International said reports that a civilian and a police officer had been killed in clashes on Wednesday were "deeply disturbing". 

A night-time curfew was imposed in Dar es Salaam, with sources telling the BBC that the city's Muhimbili Hospital had seen an influx of wounded patients.

Internet connectivity remains severely disrupted across the country - a situation Amnesty warns could further inflame the situation. It called on the authorities to allow unrestricted access to information.

In the meantime protesters are said to be using a walkie-talke app, called Zello, to plan their next moves.

President Samia is widely expected to secure a second term after opposition candidates were barred from running. The poll is also anticipated to be shoo-in for her party, which has never lost an election since independence.

Tundu Lissu, the main opposition leader, is in jail on treason charges, which he denies, and his party boycotted the vote.

Sixteen fringe parties, none of whom have historically had significant public support, were cleared to contest against Samia.

The only other serious contender, Luhaga Mpina of the ACT-Wazalendo party, was disqualified on legal technicalities.

Samia came into office in 2021 as Tanzania's first female president following the death in office of President John Magufuli.

She was initially praised for easing political repression under her predecessor, but the political space has since narrowed, with her government accused of targeting critics through arrests and a wave of abductions.