A senior member of Zimbabwe's opposition MDC Alliance, Tendai Biti, has been arrested at the border with Zambia, his lawyer is quoted as saying.
Police had issued a search warrant for Mr Biti, accusing him of "unlawfully" announcing that his party's leader, Nelson Chamisa, won last Monday's presidential election.
He is also accused of inciting the violence when MDC Alliance supporters clashed with security forces two days later, leaving six people dead.
His lawyer, Nqobizitha Mlilo, told the AFP news agency that Mr Biti had been heading to Zambia to seek asylum.
Mr Biti was the minister of finance in a unity government that was formed after disputed elections in 2008 - and is credited with helping stabilise the economy after years of hyperinflation.
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The election was won by President Emmerson Mnangagwa, but the opposition says the result was rigged.