Some 200 people fleeing warfare died after a boat crossing the Nile River sank, a South Sudanese military official said Tuesday, Jan 14, as fighting between rebels and government forces moved closer to the national capital, the Associated Press reports.

Warfare in the world's newest state has displaced more than 400,000 people since mid-December, with the front lines constantly shifting as loyalist troops and renegade forces gain and lose territory in battles often waged along ethnic lines.

Tens of thousands of residents have fled their homes to escape fighting that often pits the Dinka ethnic group of President Salva Kiir against the Nuer group of Riek Machar, the former vice president who now commands renegade forces. A boat on the Nile - fleeing the violence in Upper Nile State and carrying mostly women and children- sank, killing at least 200 people, Aguer said.

Lt. Col. Philip Aguer, the South Sudanese military spokesman, said there was fighting about 45 miles north of the South Sudanese capital of Juba.