The escalating violence in the war-torn South Sudan on record pregnant women, grandmothers and girls among 125 women rape victims. The cruelty has been most severe in the northern Rubkona county in the past week.

Medical doctors testified that some victims of sexual violence by militants were aged under ten years while others were older than 65.

"Even pregnant women have not been spared from these brutal attacks," said Ruth Okello the midwife for Médecins Sans Frontières (MSF)/ Doctors Without Borders.

Speaking from Bentiu, Okello said in addition to being raped, survivors had been whipped, beaten or clubbed with sticks and rifle butts.

Others have been robbed of their clothes, money and ration cards to receive food distributions.

"In more than three years working in South Sudan, I have never seen such a dramatic increase in survivors of sexual violence arriving at our programmes looking for medical care," Okello said.

The incidences of sexual and gender-based violence coincide with an increase of population movements as people try to reach food distributions in the Rubkona area.

South Sudan is the world';s newest country after attaining independence from Sudan in 2011.

The country of some 13 million people spilled into a civil war two years later in the wake of a fallout between its liberators.

Rebel forces have flouted a peace agreement signed in August with the government following talks in Sudan.