LUSAKA — Hakainde Hichilema was sworn in for a second five-year term as Zambia's president on Sept. 1, the same day opposition leader Brian Mundubile faced a treason charge after being taken into custody by security forces following weeks of post-election tension.

The Electoral Commission of Zambia declared Hichilema the winner of the Aug. 13 presidential poll with 60 percent of the vote. Mundubile, who leads the National Restoration Party Under People's Unity, or NRPUP, received 38 percent. Hichilema's margin left no ambiguity in the official count, but the days that followed produced a deepening political crisis.

The morning after the vote, security forces raided a property in Lusaka linked to Mundubile. A former cabinet minister was killed in the raid, and a number of other politicians were arrested. Zambian authorities accused the opposition of planning an armed insurgency. NRPUP denied the allegation.

Mundubile went into hiding after the raid, his party said, sheltering at a secure location before he and his running mate, Makebi Zulu, took refuge with the United Nations in Lusaka. They were detained after Hichilema put pressure on the UN to hand them over, according to the opposition party's account.

State broadcaster ZNBC reported Thursday that both men were being questioned by law enforcement officers in the presence of their lawyers following a summons related to what police described as activities with the potential to threaten national security. Mundubile faces a formal treason allegation.

The opposition had no avenue to contest the election result through the courts. Zambian authorities sealed off the courts on Monday — the final day a legal challenge could be filed — making any formal electoral petition impossible. Rights groups and analysts said the closure effectively prevented the NRPUP from pursuing a constitutional remedy.

The sequence of events drew criticism from international observers. Rights organizations characterized the post-election period as damaging to Zambia's democratic standing. Analysts quoted in regional reporting said the episode tarnished a country that had, in prior election cycles, been cited as a relative model for peaceful transfers of power in southern Africa.

Hichilema came to power in 2021 after defeating then-President Edgar Lungu in a vote widely praised as credible. His first-term government had emphasized economic reform and anti-corruption measures. The Aug. 13 result extended his mandate, but the circumstances surrounding his opponent's detention have complicated the picture abroad.

Mundubile's arrest places Zambia in a category of post-election disputes where the losing candidate faces criminal jeopardy rather than a ballot recount. The treason charge, the most serious available under Zambian law, carries potential penalties up to and including the death penalty.

The United Nations' role in the sequence is notable. Diplomatic norms generally protect individuals sheltering with UN facilities from forced removal by host governments, but the details of how Mundubile and Zulu were ultimately transferred to police custody were not fully disclosed in official statements.

With Mundubile in custody and the courts having been unavailable for a challenge during the filing window, the NRPUP has no immediate legal path to contest the official result. Zulu's detention removes the party's second-ranking official from the political field at a critical moment.