by Denis Elamu and Daniel MajakNAIROBI, March 23( Xinhua)--Experts on Wednesday urged the belligerent parties to the 2018 revitalized peace deal in South Sudan to immediately enter into dialogue after the main opposition party led by First Vice President Riek Machar withdrew from participating in the security mechanisms. The Sudan People's Liberation Movement/ Army-in opposition( SPLM/ A-IO) on Tuesday announced its withdrawal from the vital security mechanisms key to salvaging the fragile peace