[Breaking news update, posted at 6:51 p.m. ET]
Emmerson Mnangagwa has been declared winner of Zimbabwe's presidential election, according to the country's Electoral Commission. Mnangagwa received 50.8% of the vote, said Priscilla Chigumba, commission chairwoman. Opposition party members were escorted out of the room before the final vote was read.
[Previous story, posted at 6:18 p.m. ET]
President Emmerson Mnangagwa leads Zimbabwe's presidential election returns in nine out of 10 provinces announced, the country's electoral commission said Thursday.
Mnangagwa has 2,147,505 votes to 1,929,704 for Nelson Chamisa, 40, leader of the opposition Movement for Democratic Change in the nine provinces, according to the Zimbabwe Broadcasting Corporation.
The commission adjourned for an hour late Thursday before announcing results for the remaining province and the election winner amid fears of further unrest and claims of vote-rigging by opposition parties.
On Wednesday, six people were killed in clashes between opposition protesters and security forces in the capital Harare, prompting statements of concern from the United States, the United Nations and the United Kingdom.
The bloodshed cast a pall over Monday's elections, the first since veteran leader Robert Mugabe was deposed.
Mnangagwa, who took over the ruling Zanu-PF party from Mugabe last year, called for an independent investigation into the violence.
Soldiers spent Thursday morning clearing the central business district of Harare and warning people to leave by noon. Taxi ranks were full of commuters attempting to find a way out. Shop fronts were locked, and riot police surrounded the headquarters of the opposition MDC and blocked off nearby streets.
Police arrested 18 people during a raid at the MDC headquarters, Zimbabwe Republic Police spokeswoman Charity Charamba said. The charges were not immediately clear, but Charamba said, in total, officers have taken into custody 26 people suspected of inciting violence during Wednesday's protests.
International monitors had called on officials to publish the results of the closely fought presidential race promptly. Partial results of the parliamentary vote, announced Wednesday, gave Zanu-PF two-thirds of the seats in the National Assembly's lower house but prompted accusations of poll-rigging.
As police surrounded the MDC building on Thursday, the party's spokesman had insisted that Chamisa was set to win the presidential vote.
"We have collated results from the 80% of the polling stations that we're allowed to do so and we're very clear that we're going to win," MDC spokesman Nkululeko Sibanda told CNN. "There is no way with the 20% they are going to win. If the result is such that if we didn't win, then certainly it's not the reflection of what the people of Zimbabwe did on the 30th."
Chamisa himself tweeted Wednesday that he had won the presidential vote, even though results had not yet been released by the electoral commission.
On Thursday, Chamisa disputed claims by Mnangagwa that the government had reached out to discuss how to calm tensions.
"No they have not reached out," he said.
Zimbabwe is anxious to ensure the elections are considered free and fair in order to lure back foreign investment and resuscitate the country's ailing economy.
Mnangagwa, 75, took power after helping orchestrate a de facto coup against Mugabe in November. He has tried to rebrand Zanu-PF, pledging to heal divisions and rebuild the country.
Known as "the crocodile" for his political cunning and longevity, he is still widely considered to be Mugabe's man because he worked so closely with the former leader for more than 40 years, first as his special assistant during the 1977 liberation war, and later as security minister and justice minister.
Chamisa -- the country's youngest-ever presidential candidate -- had aimed to appeal to younger voters with promises of electoral reform, tax cuts and jobs.