South Sudan's President Salva Kiir has dissolved the country's transitional unity government and appointed a caretaker administration as the country prepares for its first-ever national elections.

A decree issued on Tuesday ended a power-sharing arrangement established under a 2018 peace deal that had halted years of civil war. The move raised concerns that Kiir could now wield unchecked power.

The decree, read out on national television, stated that all vice-presidents, ministers and local administrators had been removed and that the national and state assemblies had been dissolved. The judiciary and security institutions remain in place. Kiir will stay in office "during the election period until the next elected president assumes office," the decree said.

The announcement came a day after parliament approved changes to the National Elections Act that allowed Kiir to remain in power during the election period while removing all vice-presidents, who had been appointed under the 2018 peace deal.

The changes allow South Sudan to move toward elections scheduled for December 22, without first completing a permanent constitution or a census — two processes previously tied to the transition. The main opposition alliance has rejected the changes.

Elections were initially expected in 2022 but have been postponed twice. Tasks still outstanding under the 2018 peace deal include drafting a permanent constitution, registering voters and unifying armed forces loyal to rival parties. That agreement followed five years of civil war that killed approximately 400,000 people and displaced millions, according to the United Nations.

Amnesty International described Kiir's decree as a "decisive step" toward the country's first-ever elections. However, the rights group's regional director for East and Southern Africa, Tigere Chagutah, urged authorities to "ensure that a conducive environment exists for people to vote and stand in elections."

Analysts warned that the legal changes gave Kiir unfettered control. "Kiir will be the only person in power, without vice-presidents, without the executive, without the parliament," said Michael Wani, a lawyer and former member of the constitution drafting committee.

Independent analyst Machot Amuom said there was a lot of "ambiguity" in the new legislation. "The new law gives the president full powers… He can decide even not to go for elections for another year or another two years," Amuom said.

Last week, Kiir also replaced the head of the elections commission without giving a reason. The South Sudan Broadcasting Corporation said the new chief, Gabriel Bol Deng Majok, had been given a "fresh mandate" to oversee preparations for the polls.

The transition is taking place under tight security. Reports described checkpoints and road closures around the government complex in the capital, Juba, while security personnel were ordered to remain on heightened alert for three days.

Kiir's longtime rival Riek Machar, who leads the opposition Sudan People's Liberation Movement-in-Opposition, remains under house arrest. He is on trial on charges including treason and murder, which he denies.