Zambian opposition leader Brian Mundubile and his presidential running mate Makebi Zulu have been arrested on treason charges, police confirmed on Thursday, after the pair were taken into custody at the United Nations country office in Lusaka, the Zambian capital, where they had sought refuge. The arrest marks a sharp escalation in the political crisis that has gripped Zambia since its presidential election on 13 August.

Mundubile, a 55-year-old lawyer and leader of the National Reconciliation Party for Unity and Prosperity (NRPUP), came second in this month's vote with 38 percent of the ballots cast, according to official results that showed incumbent President Hakainde Hichilema winning re-election with over 60 percent. The day after the election, police special forces raided a property belonging to Mundubile in the Kabulonga neighbourhood of Lusaka, reporting the discovery of a weapons cache and alleging the existence of illegal military training camps and preparations for an armed uprising. Former cabinet minister Mutotwe Kafwaya was shot during the raid and later died of his wounds; eleven others were arrested. Mundubile dismissed the allegations as