An electoral worker carries and stacks ballot boxes at an electoral commission office in Kano, in northern Nigeria Sunday, Feb. 24, 2019. Vote counting continued Sunday as Nigerians awaited the outcome of a presidential poll seen as a tight race between the president and a former vice president. (AP Photo/Ben Curtis)

KANO, Nigeria - Nigeria faced a second day of voting in scattered areas Sunday in a presidential election seen as too close to call, while the death toll from vote-related violence mounted in Africa's largest democracy.

The electoral commission said voting was generally peaceful, but it mourned the killing of one of its workers by a stray bullet in Rivers state in the restive south. At least 39 people had died in extremist and other attacks, said analysis unit SBM Intelligence, citing informants and media reports.

More than 72 million people had been eligible to vote in Africa's most populous country and largest economy. The election was held a week late after the electoral commission at the last minute cited several logistical challenges.

President Muhammadu Buhari, a former military ruler who unseated the incumbent in the 2015 election, seeks a second term against more than 70 candidates. His main rival is Atiku Abubakar, a former vice-president who has made sweeping claims of reviving an economy still limping back from a rare recession.

Voting continued in parts of Abia, Bayelsa, Benue, Plateau, Zamfara and Sokoto states after the process was extended because of various issues.

"Nigerians have demonstrated extraordinary resilience and abiding faith in the electoral process," electoral commission chairman Mahmood Yakubu said.

Official results could come as early as Monday. Meanwhile, observers warned of potential thuggery as local officials raced to compile votes across the country.

Yakubu said some election workers had faced "intimidation, abduction, hostage-taking and violence." In one case, he made an urgent phone call to secure the release of workers and police taken hostage in Rivers state. All were unharmed, he said.

Nigerian police said 128 people had been arrested in suspected vote-related offences, including ballot box-snatching, vote-trading and impersonation, while a "cache of explosives" was found. Police called the election generally successful, though it expressed concern about hate speech by some politicians and supporters.

Many Nigerians, appalled that their country recently became the world leader in the number of people living in extreme poverty, said the election will be decided by economic issues. Nigeria slipped into recession under Buhari when global oil prices crashed, with unemployment growing significantly to 23 per cent and inflation now above 11 per cent.

One of the largest domestic observer groups, Watching the Vote, said Nigeria had missed its chance to improve on the 2015 election, seen as one of the most transparent in the country's history.

Logistical problems caused 59 per cent of the polling stations monitored to open late, but delays and misconduct at some stations didn't necessarily undermine the election's credibility, spokesman Hussaini Abdu said.

In the northern city of Kano, tempers flared at one vote compilation centre where Abubakar supporters alleged that ballots from a couple of polling units hadn't been counted. Amid shouting, security personnel ejected them.

A ruling party supervisor, Joy Bako, watched in exasperation after she spent a sleepless night standing guard over results, like many party agents across the country.

"It was free and fair," she said. "Nobody was arguing. I'm surprised at all this noise."

Even one Abubakar supporter, Abubakar Ali, paused from the ruckus to acknowledge that everything had been "going clear." But many people didn't come out to vote as compared to 2015, he said.

Godwin Ugbala, an agent for one of Nigeria's dozens of small political parties, also reported a smooth voting day. He added his voice to many Nigerians' frustration with Buhari, though some said they saw no other option.

"This one failed us in so many ways," Ugbala said. "No business. Everything is tired." He voted for Buhari in 2015 but said the president had "betrayed" the people by not following up on promises to tackle insecurity and corruption.

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Associated Press writer Cara Anna reported this story in Kano, Nigeria, and AP writer Rodney Muhumuza reported from Yola, Nigeria.

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Follow AP's full coverage of the Nigeria elections here: https://www.apnews.com/Nigeria

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News from © The Associated Press, 2019