NAIROBI, Kenya (AP) — Tanzania’s leading opposition candidate has rejected Wednesday’s presidential vote after alleging widespread irregularities, saying on Thursday that whatever happened was not an election and was like “spitting in the face of democracy."

Tundu Lissu of the CHADEMA party also appeared to warn of unrest: “Those in power are telling Tanzanians, ‘If you want change, look for it another way, not through the ballot box, not through democracy,’” he told reporters. “The message they are sending is, ‘Use force if you can ... We won't let you win through democracy. If you want, use force.'"

He added, however, that unlike the government, “we do not have the instruments of violence," and he called for protests by democratic means. He also called for international pressure and condemnation of the election process.

Lissu, who survived an assassination attempt in 2017 and returned from exile this year, said he won't accept the results, asserting that thousands of observers were turned away from polling stations and those who managed to enter were not given official results.

The other top opposition party, ACT Wazalendo, announced that its presidential candidate in the semi-autonomous region of Zanzibar, Seif Sharif Hamad, was arrested Thursday for the second time in a week.

The East African nation’s electoral commission has denied allegations of irregularities as populist President John Magufuli seeks a second five-year term in one of Africa's most populous countries and fastest-growing economies. Results could be announced Friday.

The commission on Thursday released results for 18 out of 264 constituencies showing Magufuli with the early lead. The ruling Chama Cha Mapinduzi party, in power since independence in 1961, also has won a majority of seats in the legislative assembly.

The election turnout appeared to be below 50%, according to the early figures. Some 29 million people had registered to vote.

Magufuli has been widely criticized for repressive measures against dissenting voices, including a ban on opposition political gatherings in 2016 and the targeting of media outlets.

Many across Africa have watched in dismay at what they've described as Tanzania's turn away from its long reputation for democracy.

“Tanzania championed freedoms and the independence of the continent, including leading the formation of the African Union ... many people look at Tanzania for a sense of prestige and pride,” Deprose Muchena with Human Rights Watch told a briefing Thursday. “Today, all those ideals are being contested.”

Tanzania Elections Watch, a regional group of eminent persons, expressed concerns about the conduct of the election, noting deadly violence on the eve of the vote in Zanzibar, a massive disruption in internet and text messaging services and the reported arrests of other candidates on election day.

“Unfortunately, in Tanzania the announcement made by the National Electoral Commission is final,” the group's co-chair Frederick Ssempebwa told a briefing, as results cannot be challenged in court. “There is no avenue for the aggrieved parties to air their views.”

The declaration of results could trigger a wave of instability, Ssempebwa said.