South Sudan's fragile political balance shifted into crisis on Thursday night after President Salva Kiir suspended his longtime rival, First Vice President Riek Machar, alongside Petroleum Minister Puot Kang Chuol.

The move came just hours after the two opposition leaders were formally charged with treason.

The decree, read out on state-owned South Sudan Broadcasting Corporation, struck at the heart of the Sudan People's Liberation Movement/Army-In Opposition (SPLM/A-IO)—the rebel faction turned uneasy peace partner under the 2018 revitalised accord.

Justice Minister Joseph Geng Akech told reporters earlier in the day that Machar, Kang, and six other senior SPLM-IO leaders faced treason and murder charges linked to March 2025 clashes in Nasir.

Investigators, he said, had found evidence that they coordinated with armed youth militias known as the White Army.

"The following eight accused persons have been charged: Dr. Machar Teny Dhurgon, Kang Chol, Lt-Gen Gabriel Duop Lam, Mam Pal Dhuor, Gatwich Lam Puoch, Brig-Gen. Camilo Gatmai Kel, Mading Riek Yak and Dominic Gatrgok Riek," Akech announced.

The clashes in Nasir were among the deadliest since the 2018 deal, leaving dozens of government soldiers dead, including senior commanders, and triggering aerial bombardments in which rights groups alleged chemical components were used.

Thousands were displaced, reigniting bitter distrust between SPLM-IO fighters and the South Sudan People's Defence Forces (SSPDF), which were supposed to merge into a unified army.

Machar has been under house arrest since security forces stormed his residence in March, while Kang remains in custody..

Their detention reignited skirmishes across the country between SPLM-IO loyalists and government troops, raising fears of a wider return to war.

For Kiir, the suspension is both tactical and risky. It sidelines his most potent rival, but also threatens to unravel the delicate power-sharing formula that has held since 2018.

Analysts warn it could further stall preparations for elections already long delayed.

"Based on evidence, the following charges were prepared under South Sudan laws and applicable international laws. One, murder... in particular the killing of Major General David Majur, 250 SSPDF soldiers and UN personnel," the Justice Minister said bluntly.