ON THURSDAY, current president and ruling-party leader Emmerson Mnangagwa was declared the winner of Zimbabwe’s first election since Robert Mugabe’s ouster from power.

Mr. Mnangagwa scraped by with 50.8 percent of the popular vote, narrowly avoiding a runoff against opposition leader Nelson Chamisa. The election — which saw a high turnout of approximately 70 percent — should have been a moment of celebration as the country turned the page on Mr. Mugabe’s misrule and started a new chapter of democratic governance.

Instead, it was marred by violence and allegations of fraud as authorities cracked down on the opposition and opened fire on protesters in the center of Harare.

This was a sad end to an election that had raised hopes but also concerns from the outset. International observers had initially found problems during the campaign, noting that state-sponsored media coverage was biased toward Mr. Mnangagwa and that his party appeared to be distributing food and aid on partisan grounds. They also found evidence of voter intimidation across the country and irregularities in the ballots and at polling stations.

Suspicions about impropriety were heightened by the four-day delay in announcing the results, which fed into “suspicions, tensions and volatility,” according to former Liberian president and election observer Ellen Johnson Sirleaf.

As delays continued, thousands of Mr. Chamisa’s supporters took to the streets on Wednesday to protest what they perceived as vote rigging by the government. Some of them threw rocks, burned tires and destroyed benches, street signs and stoplights. In response, the army inexcusably directed a rain of bullets at demonstrators, killing at least six and injuring many more.

Security forces allegedly patrolled the city beating up civilians, while police officers raided the headquarters of the opposition party and reportedly detained 16 officials for questioning. The opposition has since rejected the results, calling them “unverified” and “fake.”

Despite his checkered past as an official in Mr. Mugabe’s government, Mr. Mnangagwa has claimed he wants “a new beginning” for Zimbabwe. Yet the actions of security forces this week have seemed more like a page out of the old playbook.

It is now incumbent on Mr. Mnangagwa to show that he is serious about change. The opposition has some legitimate concerns about the election that need to be addressed, and, as the country sits on a knife’s edge, he needs to take the lead in pushing for transparency and calling for calm.

He should immediately remove armed forces from the streets, end the harassment of opposition leaders and take steps to hold the abusive soldiers accountable. The Zimbabwe Electoral Commission, meanwhile, should release results from individual polling stations so the results can be verified.

The U.S. Embassy in Harare released a statement expressing concern, and other leaders soon followed suit. This is a start, but the international community must continue to bring pressure on the Zimbabwean government.

The United States and European Union had previously emphasized that a credible election was a condition for lifting the sanctions imposed on officials in Mr. Mugabe’s government or backing an International Monetary Fund bailout of Zimbabwe.

They should continue to push for transparency and reform, or the country could find itself ruled by a strongman yet again.

August 3 at 7:06 PM