South Sudan 'most difficult place' in the world for aid workers

South Sudan is the most difficult place in the world for aid workers, a senior UN official said on Friday, with at least 15 killed so far in 2017.

Since the four-year conflict began at least 85 humanitarian workers have been killed in the country in attacks by both government army forces and rebels, with most of the victims South Sudanese.

"I have worked all over the world but I can't think of a more difficult place to work than here logistically in terms of the conflict, the need is sort of a perfect storm in terms of difficulty," David Shearer, head of the United Nations Mission in South Sudan (UNMISS), said.

Speaking during an event in Juba to mark World Humanitarian Day, Shearer said more must be done to respect aid workers and protect their lives.

"We should acknowledge that we are in an enormous number of places across South Sudan, and if you were not there, there would be tens of hundreds of people who wouldn't be alive today," he said, according to the Sudan Tribune.

The acting head of the UN Humanitarian Coordination Office (UNOCHA) in South Sudan, Serge Tissot, said on Saturday that attacks on aid workers are increasing, together with the looting of UN warehouses and the loss of tons of food.

"We continue to witness increasing, deliberate and unprovoked attacks against civilians and aid workers in South Sudan. This should not be accepted as the norm," Tissot said, according to the UN.

Since January, 27 security-related incidents have forced the relocation of some 300 aid workers, while 630 incidents of attacks on aid compounds, convoys and looting have been reported.

The four year conflict has divided South Sudan along ethnic lines and forced over two million to flee the country.

More than one million people have fled to neighbouring Uganda, with another million seeking refuge from the brutal civil war elsewhere in the region, the UN says.