Biti, a veteran figure in the opposition Movement for Democratic Change (MDC), was taken handcuffed into a courtroom in Harare under a heavy police presence to face charges of public violence as well as the illegal declaration of election results.
"We will keep on fighting," he told reporters, before being granted bail of USD 5,000 on the condition that he surrenders his passport and does not address any political gatherings or news conferences.
Biti made a dash across the border Wednesday, facing allegations of inciting protests last week by proclaiming victory for the opposition in Zimbabwe's first elections since the downfall of Robert Mugabe in November.
Mugabe's successor at the head of ruling party ZANU-PF, Emmerson Mnangagwa, was later declared the winner according to the official results, but the MDC claims the election was rigged.
The UN refugee agency said it was "gravely concerned" by reports that Biti, an internationally-respected finance minister in Zimbabwe's 2009-2013 power-sharing government, had been deported while trying to claim asylum.
"Forcibly returning refugees and asylum-seekers to their country of origin is a serious violation of international refugee law," the UNHCR said in a statement. It urged Zambia to investigate the incident, which comes after accusations that Zimbabwe's authorities are pursuing a heavy crackdown on the opposition as it pursues its claims of electoral fraud.
Zambian government spokeswoman Dora Siliya said authorities had only received the ruling from its own court blocking Biti's expulsion after he had been returned. "His asylum was denied on the basis that in his country there is no breakdown in the rule of law," she told AFP, adding that Biti himself was "running away from the due process of the law" as he was wanted by authorities.
Western nations said they were "deeply disturbed by continuing reports that opposition supporters are being targeted by members of the Zimbabwean security forces".
In a joint statement, the EU, US, Canadian and Australian missions to Zimbabwe urged authorities to guarantee Biti's safety and human rights. "The charges are worrisome on the face of it," said US ambassador Brian Nichols, who attended the court hearing.
He added that he had spoken with Biti who "appears in good condition", and whose legal team are seeking to have the charges overturned.
At a packed court hearing, prosecutors accused Biti of egging on protesters on August 1, urging them to pull down a Mnangagwa campaign poster while telling them: "Remove that poster, we don't want thieves in this country."
The protesters went on to burn the poster while damaging property at the Harare offices of ruling party ZANU-PF.
The army opened fire on protesters that day, killing six people and prompting an international outcry.
Mnangagwa, who is seeking to reverse Zimbabwe's economic isolation and attract desperately needed foreign investment, had vowed the elections would turn a page on Mugabe's repressive 37-year rule.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)