The UN refugee agency says it has 'grave concerns' over the reported forced return of a Zimbabwean opposition politician who was seeking asylum in Zambia.
Tendai Biti - a former finance minister turned opposition figure - is said to have been deported from Zambia after authorities rejected his asylum bid.
He is said to have been handed over to authorities in Zimbabwe despite a court order halting the deportation.
Mr Biti had attempted to flee as he was being sought in his home country for allegedly stoking violence following the recent Zimbabwean election.
Mr Biti is further accused of 'falsely and unlawfully' announcing election results, according to Reuters.
Other opposition figures, including presidential candidate Nelson Chamisa, are also said to be under investigation.
The return of the Mr Biti to Zimbabwe has provoked international condemnation.
The EU, US, Australia and Canada said they were 'deeply disturbed' by the reports.
Joint Local Statement by the EU Delegation, the EU Member States in Harare, and the Embassies of Australia, Canada and the United States of America on the targeting of opposition in Zimbabwe. pic.twitter.com/mUu8ilTjBK
— EU in Zimbabwe (@euinzim) August 9, 2018
The UN Refugee Agency (UNHCR), meanwhile, said: "A senior Zimbabwean politician expressed the intention to seek asylum in Zambia at the border yesterday. It is reported that the authorities handed him over to his country of origin today despite a court order to the contrary.
"Refoulement or forcibly returning refugees and asylum-seekers to their country of origin is a serious violation of international refugee law. UNHCR calls on Zambia to investigate this reported incident urgently."
Mr Biti has since appeared in court and has been released on bail.
Addressing reporters, he pledged to 'keep on fighting'.
Last week, Zimbabwe's electoral commission announced that President Emmerson Mnangagwa - leader of the ruling Zanu-PF party - had narrowly won the first presidential vote in the country since the ousting of Robert Mugabe last year.
Opposition leaders have vowed to challenge the result in court, having previously described the results as 'fake'.
President Mnangagwa, meanwhile, today claimed Mr Biti had been released following his 'intervention'.
However, he added: "No one is above the law. Thus due to the serious nature of the allegations of incitement, due process will continue."
STATEMENT ON RELEASE OF TENDAI BITI
Tendai Biti was released earlier today following my intervention.
At such a crucial time in the history of the new Zimbabwe, nothing is more important than unity, peace and dialogue. (1/3)
— President of Zimbabwe (@edmnangagwa) August 9, 2018