Police officers keep watch over supporters of the Movement for Democratic Change (MDC) opposition party of Nelson Chamisa as they march on the streets of Harare, Zimbabwe, August 1, 2018. REUTERS/Siphiwe Sibeko

HARARE (Reuters) - Zimbabwean police fired tear gas in central Harare on Wednesday to disperse stone-throwing supporters of the opposition MDC party, according to Reuters witnesses and live television images.

Earlier, MDC leader Nelson Chamisa wrote on Twitter that he had won the “popular vote” in this week’s presidential election, in which he faced off against President Emmerson Mnangagwa from the ruling Zanu-PF party.