A presidential spokesman says South Sudan's ruling party has dissolved its leadership secretariat in a move that could raise political tensions following a peace deal with rebels.

Ateny Wek Ateny said Saturday that President Salva Kiir remains chairman of the party, known as SPLM, and will appoint a new leadership at an upcoming national convention.

The decision reverses steps made toward reunifying the party, which ruled South Sudan as a de-facto one party state since independence from Sudan in 2011 but splintered two years later with the outbreak of a rebellion.

Kiir heads the government while his former deputy, Riek Machar, leads an armed breakaway group.

James Gatdet Dak, a spokesman for Machar, accused Kiir of trying "to split the SPLM permanently."