Top ministers from four regional nations flew to troubled South Sudan Thursday to kick start efforts to end days of fighting that has raised fears of a return to civil war in the young country.

Kenya's Foreign Minister Amina Mohammed, who said she was "en route to South Sudan to offer first hand assistance", told AFP she was with teams from Djibouti, Ethiopia and Uganda.

"It's a regional issue and the government of Kenya must be part of the solution process," she said.

All are members of the regional body, the Inter-Governmental Authority on Development(IGAD), whose members played key roles in pushing forward the 2005 deal that ended Sudan's two-decades long civil war with the south.

Rwandan foreign minister Louise Mushikiwabo offered her support.

"We pray our brothers and sisters find room to talk and agree a way forward," she said.