South Sudan's opposition party has demanded the release of Riek Machar's spokesperson, James Gatdet Dak.
This follows his reported arrest by Kenyan security agencies.
Miyong Kuon, Sudanese People's Liberation Movement-In Opposition(SPLM-IO) representative to the UN, said in a letter on Wednesday that they have reports that Gatdet is set to be deported.
SPLM condemned the act, terming it a violation of the United Nations charter on Freedom of expression and association, and added that Gatdet should be accorded asylum in a safe country.
They termed the incident unfortunate and one that should be highly condemned by all state leaders including Kenya.
"It is unfortunate that the Kenyan government wants to take this unwelcoming move of handing over an opposition spokesperson to a government that killed its own people," read part of the letter.
However Southern Sudanese Ambassador Mariano Deng dismissed the possibility of the arrest.
He noted Kenya's relationship with his country will not be affected.