South Sudan's President Salva Kiir has sacked two of his vice-presidents, the country's spy chief and other senior officials.

The dismissals were announced in a series of presidential decrees read on the state broadcaster. No reasons were given for the move.

South Sudan has five vice presidents as part of a 2018 peace agreement to end a civil war.

The oil-rich nation became the world's newest country in 2011 after seceding from Sudan - but it was then engulfed by civil war after Kiir and his deputy Riek Machar fell out. The 2018 power-sharing agreement has been fraught with problems.

One of the vice presidents removed from office is James Wani Igga, a veteran politician and general, who has been in the position since 2013 and has been the deputy chair of SPLM, the party of the president.

The other is Hussein Abdelbagi Akol, from an opposition alliance (SSOA) which is not part of the main opposition movement (SPLM-In Opposition) of First Vice-President Riek Machar.

Akol has been appointed the minister for agriculture, replacing Josephine Joseph Lagu from the same SSOA alliance who now becomes a vice president.

Benjamin Bol Mel, who was sanctioned by the US in 2017 for alleged corruption, has been appointed to replace Igga as vice president.

Mel, previously a special presidential envoy for special programmes, has been the subject of speculation that he was being fronted as a potential successor of Kiir.

The president has not appointed replacements for the health minister and the governor of the southwestern state of Western Equatoria, who are both from Machar's party.

He has also not appointed a substantive replacement for the sacked spy chief, Akec Tong Aleu, who had only served four months after having been appointed in October.

The 2018 peace deal gives the president the prerogative to appoint and dismiss government officials at both national and state levels.

He can only appoint and dismiss officials who belong to other political parties with the consent of the leadership of those parties.

It is not clear whether the dismissal of the Western Equatoria governor and the health minister was recommended by their party leader, Machar. The SPLM-In Opposition has not commented on the matter.

South Sudan has not conducted an election since independence.

The first nationwide vote was scheduled to take place in 2015, but the election could not go ahead due to the conflict that erupted in December 2013.

It was then supposed to happen in 2022, but polls were postponed for two years and were due two months ago.

The vote was postponed again, and the country's leadership said the election will now take place in December 2026.