Lusaka - Zambia's main opposition leader, Hakainde Hichilema, has been charged with treason after he was accused of obstructing the motorcade of President Edgar Lungu.
Under the country's penal code, treason carries a death sentence.
Authorities allege that Hichilema, leader of the United Party for National Development, blocked Lungu's motorcade with his own convoy of vehicles during a traditional ceremony in Zambia's Western Province over the weekend. They say Hichilema's motorcade did not yield after presidential security guards signalled for it to get out of the way.
The opposition party has denied any wrongdoing. Hichilema was taken to a police station in Lusaka on Tuesday after officers raided his home overnight. Treason is a non-bailable offence under Zambian law, meaning that he will stay in custody until trial.
"The charge is nonsensical and no sensible lawyer can come up with such a charge," said Hichilema's lawyer, Jack Mwiimbu. "The unfortunate part is that the police are being unprofessional considering that it is the (ruling party) who have been proposing that HH must be charged with treason."
Hichilema, who lost an August election to Lungu, the incumbent, alleged polling irregularities after the vote and went to court. The nation's top court then rejected an opposition petition to block Lungu's inauguration.
Hichilema has refused to recognise Lungu as president, arguing that his party still has a case pending and could only recognise him once that is dealt with.