South Sudan's army denies charges that its forces killed 14 civilians in the northwestern town of Raga.

Col. Santo Domic Chlo, acting spokesman of the army, said the report from South Sudan's opposition is a lie.

Opposition spokesman Lam Paul Gabriel said troops attacked the town late Saturday morning.

The report of fighting in Raga comes after residents of the western town of Wau reported ethnically targeted attacks last week, with the U.N. mission in South Sudan saying its workers had seen the bodies of 16 civilians.

South Sudan's three-year civil war has grown more intense in recent weeks. U.N. officials repeatedly have warned of the risk of genocide.

The acting envoy of the U.N. secretary-general, Moustapha Soumare, urged both sides to show restraint and protect all South Sudanese citizens.