Tanzanian police ordered a curfew in Dar es Salaam on Wednesday after violent protests marred an election that President Samia Suluhu Hassan is expected to win following the disqualification of two leading opposition candidates.

Internet service was disrupted across the country, monitor group NetBlocks said, as videos of young protesters hurling stones at security forces and a petrol station in flames circulated on social media.

Witnesses reported aggressive demonstrations in several neighbourhoods of Dar es Salaam, the country’s main city, including the burning of a local government office.

Video posted on X by the leading opposition party showed dozens of young men running through the streets of the northern city of Arusha, columns of dark smoke rising behind them, chanting: “We want our country!”

Protesters are angry about the banning of the two leading opposition candidates from the election and a wave of alleged abductions of government critics. They were coordinating on the Zello app, which allows a smartphone to function like a walkie-talkie.

Government and police spokespeople did not respond to requests for comment. The government has said the election is being conducted fairly and denied allegations of widespread human rights abuses in the run-up.

The police curfew started at 6pm local time (1500 GMT), and the US embassy said American government personnel had been advised to shelter at their residences.

Chadema had called for protests during the election, which it said amounted to a “coronation” of Hassan, who came to power in 2021 after her predecessor died in office. The party was disqualified in April after it refused to sign a code of conduct, and its leader Tundu Lissu was charged with treason.

The commission also disqualified Luhaga Mpina, the candidate for opposition party ACT-Wazalendo, leaving only minor parties to take on Hassan.

Turnout appeared low at polling stations, which closed at 4mp. Results are expected within three days.

After voting in the administrative capital Dodoma, Hassan told reporters: “I urge all Tanzanians, those who are still at home to come out and exercise their right and vote and choose their preferred leaders.”

Voters were also choosing members of the country’s 400-seat parliament and a president and lawmakers in the semi-autonomous Zanzibar archipelago.

Hassan’s CCM, whose predecessor party led the struggle for independence for mainland Tanzania in the 1950s, has dominated national politics since it was founded in 1977.

Hassan, one of only two female heads of state in Africa, has been touring the country of around 70 million people to tout her record of expanding transport networks and increasing power generation. Initially, she won plaudits for easing repression of political opponents and censorship that proliferated under her predecessor, John Magufuli.

In recent years, however, rights campaigners and opposition candidates have accused the government of unexplained abductions of its critics.

Hassan said last year she had ordered an investigation into reports of abductions. No official findings have been made public.

• A Reuters report