President Emmerson Mnangagwa of Zimbabwe claimed victory on Saturday in an election marred by widespread allegations that the governing party, ZANU-PF, had committed fraud.
Mr. Mnangagwa’s victory over his closest competitor, Nelson Chamisa, after his first full term in office strengthened ZANU-PF’s grip on power in a nation it has led since independence from Britain in 1980. Over the past two decades, Zimbabwe has suffered under disastrous economic policies that have led to soaring prices, high unemployment and a medical system lacking basic drugs and equipment.
Mr. Mnangagwa won 52.6 percent of the vote compared with 44 percent for Mr. Chamisa, according to the Zimbabwe Electoral Commission, which is responsible for running the election and has faced withering criticism of showing bias toward ZANU-PF.
Mr. Chamisa’s party, Citizens Coalition for Change, quickly denounced the results and vowed to challenge them.
“We reject any result hastily assembled without proper verification,” Promise Mkwananzi, the party spokesman, wrote on Twitter shortly after the results were announced. “We will not relent on the people’s victory!”
With Mr. Mnangagwa, 80, winning another five years in office, Zimbabwe is likely to continue to struggle to break out of its isolation from Western nations, which have demanded greater democracy and respect for human rights in exchange for helping it grapple with $18 billion in debt.
Zimbabwe, a southern African nation of 16 million, has a history of election irregularities, and such tactics helped Robert Mugabe, a liberation leader turned autocrat, maintain power for nearly four decades. Mr. Mugabe was removed in a coup in 2017 by Mr. Mnangagwa and his allies. The following year, Mr. Mnangagwa eked out a victory over Mr. Chamisa in an election, winning just over 50 percent of the vote.
This year’s voting, held on Wednesday, was marred by chaotic delays of more than 10 hours at some polling locations because the country’s electoral commission failed to deliver ballots on time. Thousands of voters found themselves camping overnight at polling stations because of the delays, which mostly affected urban areas, where Mr. Chamisa and his party hold most of their support.
The Zimbabwean police drew global condemnation for arresting dozens of members of one of the country’s most respected election watchdogs on election night, accusing them of plotting to sow discord by releasing projected election results. The night after the raid, ZANU-PF officials offered their own election projections at a news conference, and drew no ire from the police.
Before the results were announced, several independent foreign observer missions criticized the fairness and credibility of the elections. The European Union’s mission offered among the most biting critiques, saying in a statement that the government curtailed fundamental freedoms by passing repressive laws “and by acts of violence and intimidation, which resulted in a climate of fear.”
Although Election Day was peaceful, “the election process fell short of many regional and international standards, including equality, universality and transparency,” the statement said.
Christopher Mutsvangwa, the spokesman for ZANU-PF, said the allegations of vote rigging were “all humbug.” The election mechanics were foolproof, he said, with agents from every party allowed to observe the vote counting and sign off on the results in each precinct.
“We have shown the whole world that we have exercised democracy,” he said.
Before the voting on Wednesday, ZANU-PF used the machinery of the state to shut down opposition rallies and try to get candidates thrown off the ballot in court, analysts said. The governing party also deployed Forever Associates Zimbabwe, a pseudo-military organization run by people with close ties to the government’s intelligence agency, to intimidate voters in rural communities, said Bekezela Gumbo, a principal researcher at the Zimbabwe Democracy Institute, a nonpartisan think tank in Harare, the Zimbabwean capital.
The Zimbabwe Electoral Commission is stacked with officials with ties to ZANU-PF, Mr. Gumbo said. Critics said that the commission had failed to produce a definitive voter roll and kept adjusting polling locations, potentially leading to confusion with voters showing up at the wrong places to cast their ballots.
The electoral commission blamed court challenges that held up the printing of ballots for delays in voting on Election Day. But critics noted that the delays were mostly in Harare and other urban areas that are opposition strongholds.
The commission invited all of the presidential candidates to observe the tabulation on Saturday before the results were announced.
“If this is not a demonstration of transparency, then I probably do not know the definition of this word,” said Rodney Kiwa, the deputy chairman of the commission.
On Wednesday afternoon, Mirirai Moyo, a mother of three, had returned to her market stall in a suburb of Harare after a failed effort to cast her vote in the morning. There were no ballots at her polling station, she said.
“I can’t go back because it’s late now,” she said. “It’s sad now. This is what ZANU-PF wanted because it knew there would be people like me who won’t be able to stick around the polling stations till late.”
Voters also woke up Wednesday to fliers scattered about the streets of Harare and the southern city of Bulawayo falsely claiming that Mr. Chamisa’s party was urging people not to vote, an apparent effort to suppress opposition turnout.
Near some polling sites, ZANU-PF set up tables where officials were purportedly conducting exit polls. They asked voters for their personal information and whom they voted for, and in some cases intimidated citizens before they cast their vote, according to multiple news reports and social media.
Many had held out hope that a defeat for Mr. Mnangagwa, a former guerrilla fighter in Zimbabwe’s battle for independence from British colonial rule, would represent a clean break from the suffering under Mr. Mugabe.
Under Mr. Mnangagwa’s watch, obscenely high, triple-digit inflation returned. An estimated 90 percent of the work force holds informal odd jobs, like selling vegetables by the roadside, while more educated Zimbabweans are leaving the country in growing numbers in search of economic opportunity.
Nearly six in 10 Zimbabweans believe that corruption has grown worse since Mr. Mnangagwa took office, and more than 70 percent say the country is going in the wrong direction, according to Afrobarometer, a nonpartisan research firm that conducts surveys across Africa.
Supporters of the president and of ZANU-PF argued that he had set up the country for economic success by luring investors despite barriers they believe have been erected by the West. Zimbabwe sits on Africa’s largest reserves of lithium, a mineral critical for electric car batteries and other clean technologies. Chinese companies have invested hundreds of millions of dollars in lithium production in the country.
“President E.D. Mnangagwa is loved by many people because of his drive for development,” said Nyasha Musavengana, wearing a green T-shirt with the president’s picture as she participated in a rally before the election. “Brick by brick, step by step, he is fixing things in Zimbabwe.”
Although Mr. Mnangagwa has talked about deeper engagement with the United States and Europe, he has also gleefully embraced rivals of Western nations, notably China and Russia. Just weeks after attending a business conference in Botswana hosted by the United States, Mr. Mnangagwa was a darling of a Russia-Africa summit in July, where he gave a speech proclaiming his support for Russia’s invasion of Ukraine. He also cheerfully accepted Mr. Putin’s gift of a helicopter.
Mr. Chamisa, 45, presented a starkly different vision. A member of Parliament for the past 20 years as well as a lawyer and preacher, he has expressed an eagerness to re-engage with the United States and Europe. He leads a new party, Citizens Coalition for Change, and told Zimbabweans that he offered a break from the corruption of years past.
“I voted for C.C.C. because I’m tired of suffering,” said Maggie Sibanda, 70, after casting her vote near Bulawayo. “My children are in South Africa and they want to come home, but how can they when things are so bad?”
Tendai Marima contributed reporting from Bulawayo and Harare, and Jeffrey Moyo from Harare.