The UN envoy in South Sudan on Sunday called on the government to investigate and apprehend the killers of six aid workers on Saturday.

The UN Special Representative of the Secretary-General for South Sudan, David Shearer said the cold-blooded killing "is utterly reprehensible."

"The UN condemns this appalling and pointless loss of life. This cold-blooded killing is utterly reprehensible, not least, because these aid workers were dedicated to alleviating the ongoing suffering of the people of South Sudan," Shearer said in a statement issued in Juba.

"The latest attack occurred in areas controlled by the South Sudan government. The government needs to investigate and apprehend the offenders," he added.

The staff from a national non-governmental organization were reportedly ambushed in their vehicle in a government-controlled area on the Juba-Pibor road on Saturday morning.

Their bodies were found on the road by other members of the convoy who were some way behind. Their deaths bring the total number of aid workers killed in South Sudan since 2013 to around 80.

"An indication that the country is one of the most dangerous places in the world in which to be a humanitarian worker," Shearer said.

"I would like to send my condolences to the family, friends and colleagues of these dedicated aid workers," he added.

There has been a sharp increase of attacks on aid workers and their premises in the past two months, mirroring a rapid deterioration in the security and economic situation of the country.

"They should not be allowed to go unpunished. Young men are being armed without training and are able to act with impunity by all sides," he said.

The special representative who is also the head of the UN peacekeeping mission, UNMISS, called for an immediate and complete ceasefire and a resumption of peace talks.

"Otherwise, the country will continue to fracture leading to yet more uncontrolled violence," Shearer added.

source: Xinhua