JUBA, South Sudan (AP) — South Sudan's army denies charges that its forces killed 14 civilians in the northwestern town of Raga.

"This is a negative media campaign by the rebels. We didn't kill anybody, we're there to protect the citizens," said Col. Santo Domic Chlo, acting spokesman of the army. "We cannot kill citizens who we are responsible for their security. It's a complete lie."

Opposition spokesman Lam Paul Gabriel said army troops attacked Raga 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.