Zambian opposition leader Brian Mundubile has been formally charged with treason, according to his lawyer, as political tensions in the country continue to escalate.

Mundubile was taken into custody on Thursday following a violent raid by security forces that prompted him to seek refuge.

The unrest stems from Mundubile’s challenge to the outcome of Zambia’s recent presidential election.

Current president, Hakainde Hichilema, was declared the winner, securing a second term with 60% of the vote.

In contrast, Mundubile’s National Restoration Party (NRPUP) garnered 38%.

In the wake of the election, authorities accused Mundubile’s party of plotting an armed insurgency, a claim the party has vehemently denied.

On Saturday evening, Mundubile’s attorney, Milner Katolo, confirmed the treason charges against his client, noting that Mundubile is eager to address the accusations in court.

Katolo added that 17 others, including Mundubile’s running mate, Makebi Zulu, also face treason charges.

The situation escalated when, a day after the election, security forces conducted a raid at an address linked to Mundubile in Lusaka.

It resulted in the death of a former cabinet minister and the arrest of several political figures.

In the aftermath, Mundubile and Zulu sought refuge at a United Nations facility, but were later detained after intervention from the government.

The opposition’s ability to contest the election results was severely hampered when authorities sealed off the courts on the final day for filing a legal challenge.

Hichilema is scheduled to be sworn in for his second term on September 1.