Gunmen on Wednesday morning ambushed a convoy of buses on the main road connecting South Sudan’s capital with the Ugandan border, killing at least four civilians, a military official said.

SPLA spokesman Lul Ruai Koang told Radio Tamazuj that six others were wounded in the attack on the civilian convoy escorted by the military on the Juba-Nimule highway.

Lul claimed that the convoy was “targeted with heavy weapons” and that gunfire struck the civilian vehicles, saying two gunmen were also killed when security officers exchanged fire with the attackers.

He accused opposition fighters loyal to former first vice president Riek Machar of involvement in the incident.

Police spokesman Daniel Justin said the incident took place between Pageria and Moli areas.

But SPLA-IO deputy military spokesperson, Lam Paul Gabriel, denied knowledge of the deadly attack on the main road between Juba and Nimule this morning.

 “There were no any SPLA IO soldiers sent to attack public transport buses on the Nimule- Juba highway, so we are not responsible for today’s road ambush,” he said.

The highway is a lifeline for South Sudan, which imports almost everything from neighbouring countries.