The World Food Programme (WFP) on Friday condemned the killing of three workers contracted as porters by its office in South Sudan's Wau during violence earlier this week.

WFP said in statement that it learned of the death of three men, all citizens of South Sudan, on Thursday from the company that employed them, which is contracted by WFP to provide loading and unloading services at the Wau warehouse.

"We are outraged and heartbroken by the deaths of our colleagues, who worked every day to help provide life-saving food to millions of their fellow countrymen," WFP Country Director Joyce Luma said.

The UN agency said the three citizens of South Sudan appeared to have been killed on Monday as they tried to make their way to a WFP warehouse. It added that two died of machete wounds and the third was shot dead.

South Sudan has been embroiled in more than three years of conflict since December, 2013.

According to the UN, the conflict has made the East African nation one of the hostile environments for aid workers to operate as at least 79 aid workers have been killed since the civil war began.

Last month, gunmen ambushed and killed six aid workers on a road linking the capital Juba to Pibor in Boma State last month.

The UN estimates that 1.5 million people have been forced into neighboring countries and another 7.5 million people across the country are in need of humanitarian assistance and protection, and a localized famine was declared in February in parts of northern unity state.

Source: Xinhua