JUBA, Jan. 18 (Xinhua) -- Some 95 aid workers have been killed in South Sudan since the beginning of the crisis in December 2013, the UN humanitarian agency said on Thursday.

The UN Office for Coordination of Humanitarian Affairs (OCHA) said humanitarian access incidents reached new high in 2017 which saw 28 aid workers killed.

"In 2017, 1,159 humanitarian access incidents were reported by aid agencies in South Sudan. This is the highest number of incidents in a year, representing a significant increase, compared to 908 in 2016 and 909 in 2015," OCHA said in its latest Humanitarian Bulletin released in Juba.

The UN said the incidents included killing of aid workers, robbery, looting and threats or harassment, mostly affecting Juba, Rubkona and Wau counties.

During the period, aid agencies also reported at least 61 looting incidents in multiple locations in the country in 2017, with significant loss of supplies and assets.

"Other humanitarian access constraints, including active hostilities, bureaucratic/administrative impediments, operational interference and restriction of movement, increased in 2017," said the UN.

It said active hostilities and violence against personnel continued to impact humanitarian operations, with 612 aid workers relocated in 54 incidents from multiple locations across the country in 2017.

"More than half of the relocations occurred in Koch, Leer and Mayendit (Unity) and Akobo (Jonglei), where over half a million people were in need of assistance and protection in 2017," it said.

South Sudan has been embroiled in more than three years of conflict that has taken a devastating toll on the people.

According to the UN, South Sudan has become a hostile environment for aid workers to operate. In March, gunmen killed six aid workers on a road linking the capital Juba to the Eastern state of Boma.

Under international Humanitarian Law, intentional attacks against humanitarian relief personnel may constitute war crimes.