HARARE, Zimbabwe — A senior leader of Zimbabwe’s main opposition party was arrested on Thursday after Zambia rejected his request for asylum and deported him, escalating fears of a government crackdown following a disputed presidential election.

The politician, Tendai Biti, was handed to the Zimbabwean authorities at the border. He was later taken before a magistrate in Zimbabwe’s capital, Harare, and charged with inciting public violence and with violating election law by announcing unofficial results.

The magistrate, Francis Mapfumo, released Mr. Biti on $5,000 bail, and ordered him to return to court on Friday. The bail conditions also required Mr. Biti to surrender the title deeds to one of his Harare homes and to leave his passport with the clerk of court.

The events come as Mr. Biti’s party, the Movement for Democratic Change, prepares a legal challenge to the results of the July 30 election, which President Emmerson Mnangagwa won narrowly.