A convoy of U.N. barges transporting supplies to staff and displaced civilians in the Upper Nile State were attacked on Thursday, the United Nations Mission in South Sudan confirmed.
According to Voice of America, four crew members and peacekeepers were injured during the unprovoked attack, which was strongly condemned by the UNMIS, Farhan Haq, U.N. spokesman, told reporters.
"The barges came under small arms fire, and rocket-propelled grenades were also fired at the convoy of four vessels," he said.
After a mob attack on a U.N. base in the town of Bor on April 18, this is the second attack this month in which U.N. operations in South Sudan have been targeted.
Food and fuel was being carried in four barges to the U.N. base in Malakal where thousands of civilians have taken refuge from violence, VOA reported.
While the gunmen behind the attack have not been identified, the Sudan People's Liberation Army and SPLA in Opposition forces have denied responsibility of the attack and claimed that their fighters were not in the designated area.
Before setting out six days ago, the barges had been cleared by the government, the U.N. said.
A massacre in Bentiu, where more than 200 civilians were reportedly killed, and a mob attack on a U.N. base in Bor are two other recent acts in South Sudan which have been condemned by the U.N. Security Council, VOA reported.
The prospect of defusing the ongoing crisis hasn't seen any progress as neither the South Sudan government nor rebels have shown any interest in holding peace talks, U.N. peacekeeping chief Herve Ladsous said Wednesday.
"The United Nations is doing everything it can to protect the civilians that are fleeing the violence, the war," he said. "But let us never forget that the primary responsibility for protecting civilians is with the government. We are there to support but it is the government of South Sudan to make it so that its citizens are not killed."
President Salva Kiir and his rival, former vice-president Riek Machar, have been called on by the Council to publicly declare for it to be unacceptable for these attacks to be carried out on civilians.
On Wednesday, U.S. Ambassador to the United Nations Samantha Power called on the international community to sanction those who are targeting civilians or acting as "political spoilers," VOA reported.