Nicholas Haysom, special representative of the UN Secretary for South Sudan and head of UNMISS, said there are indications that recruitment could be taking place in South Sudan by parties involved in Sudan, where young men and boys are recruited to increase their forces.

"We are worried that the firearms are going to start drifting into South Sudan. These are not issues that we in UNMISS can readily deal with, we don’t maintain the border, and we don’t maintain customs, but we would be keen to alert communities and the authorities, if we can, play a helpful role to minimize what could be potentially very disruptive spillover of the conflict," Haysom told reporters in Juba, South Sudan’s capital.

He said nearly 550,000 people have crossed into South Sudan from Sudan and they expect that the number will continue to grow.

This, Haysom said, will increase stress on communities which are causing tensions among the displaced and host communities as the conflict continues.

"The longer the conflict continues, the more stress, the less able communities are to absorb newcomers. And you know it’s happening at a time in which the humanitarian food aid pot is growing smaller. And so, we are beginning to see signs of tension between the newcomers and the host communities which are looking after them," Haysom said, adding that more than 7.2 million people have been displaced inside and outside Sudan since the fighting broke out.