Arkenjelo Anyar Anyar said armed youths from neighboring Warrap state torched a local market, houses and a police station in Tharkueng Payam following a dispute over land rights.
He said the 10 dead civilians included "children, women, elderly, (who) were burned because they couldn't escape," adding that around 2,000 people were displaced or homeless.
Thirty-nine people were killed and dozens of others were wounded last Wednesday when violence broke out between rival groups of cattle herders in South Sudan's Warrap and Lake states.
One of the poorest countries on the planet despite large oil reserves, South Sudan has spent almost half of its life as a nation at war, and has also endured persistent natural disasters, hunger, economic meltdown and communal conflict.