Early results from elections in Angola have put the incumbent president, João Lourenço, and the ruling People’s Movement for the Liberation of Angola (MPLA) ahead.
The polls are the most tightly contested vote in the country’s democratic history, and have been described by analysts as an “existential moment”.
The opposition has also claimed a lead, increasing tensions and fears of unrest when full results become known in coming days.
Ballot counting began after polls closed on Wednesday, and preliminary results published overnight by Angola’s electoral commission gave the MPLA more than 60% of the vote with around a third of ballots counted.
The commission put Lourenço’s principal rival, Adalberto Costa Júnior of the National Union for the Total Independence of Angola (Unita), at 34% of votes.
The vote for Unita would be a big advance on previous elections but still far below levels needed to threaten the MPLA, in power since Angola declared independence from Portugal in 1975.
Polls before the election had showed a much closer margin of decided voters, with the MPLA only 7% ahead but with very large numbers yet to make a choice.
On Wednesday night, Unita’s deputy leader, Abel Chivukuvuku, said the party’s own tally showed it was winning.
“Our poll counting centres … give us clear provisional indication of a winning trend for Unita in all provinces of the country,” Chivukuvuku told reporters. “We are confident, calm and tranquil.”
Results in past elections have been contested, in a process that could take weeks.
Observers have warned that discontent with the rule of MPLA has reached a point where the party could only now secure another five years in power through widespread rigging and repression.
An activist monitoring group, Mudei Movement, has taken pictures of results sheets at as many polling stations as possible, fearing the fraud that marred past polls.
Unita urged voters to stay near polling stations after casting their ballots, a call many seemed to be heeding as polls closed on Wednesday evening.
“The police said to vote and go home. I told them I would vote and sit down,” said Severano Manuel, 28, in Cacuano, outside Luanda.
The electoral commission earlier said polling had gone smoothly.
Analysts say the opposition will face a dilemma if they reject official results. To instigate a campaign of street protests would leave Unita open to accusations of deliberately fomenting disorder, but to seek redress through legal or other constitutional channels is unlikely to succeed.
The elections have pitted veteran politicians in power for decades against a generation of young voters just beginning to grasp the potential to bring about a radical change.
Lourenço, a Soviet-educated former general who had promised a new era for the southern African nation when he succeeded veteran leader José Eduardo dos Santos five years ago, called on voters to recognise his achievements in power.
The 68-year-old MPLA veteran is credited withenacting some reforms, including boosting financial transparency and efficiency in parastatal organisations, and promoting business-friendly policies to lure foreign investors.
However, Lourenço has largely failed to improve the lives of most of the 35 million inhabitants. Critics say a high-profile anti-corruption drive only targeted potentially powerful enemies – such as Isabel dos Santos, the hugely wealthy daughter of the former president – while Amnesty International has described “an unprecedented crackdown on human rights, including unlawful killings and arbitrary arrests, in the lead up to the 24 August election”.
The low-key, night-time repatriation of the remains of José Eduardo dos Santos, who died in Spain last month, has added a macabre touch to the election. The former president will be buried on Sunday, which would have been his 80th birthday.
Though only eight years younger than the incumbent, Costa Júnior has tried to position himself as a representative of the young civil society and all those who have lost out under the years of MPLA rule. More than 60% of Angolans are under 24.