France, March 27 -- The political party of South Sudan's First Vice PresidentRiekMachar has warned that his arrest on Wednesday invalidates the country's 2018 peace deal.

First Vice PresidentRiekMachar, South Sudan's opposition leader, is reportedly under house arrest.

Machar'sSudan People's Liberation Movement-in-Opposition (SPLM-IO) party said that it was trying to locate him, after that the defence minister and chief of national security "forcefully entered"Machar's residence and delivered an arrest warrant on Wednesday evening.

Macharwas then held at his house overnight with his wife and two bodyguards.

He is accused of being implicated in fighting between the military and the White Army, an ethnic Nuer militant organisation, in N...