South Sudan's army has clashed with the "White Army" ethnic militia, a spokesman has said, accusing rebels of mobilising the force despite the offer of a truce to end the conflict in the country. The White Army - made up largely of Nuer youths who dust their bodies with ash to protect themselves against insects - clashed with government troops near the town of Bor five days after rebels were driven out, army spokesman Philip Aguer said on Sunday.