At least five people have been killed and 13 others injured Wednesday in an ambush along on a South Sudanese highway that connects the import-dependent young nation with Uganda, police told.

Axar.az reports that a vehicle carrying civilians from Uganda to the South Sudanese capital Juba was attacked by gunmen Wednesday afternoon 55 kilometers (34 miles) from the Ugandan border, police spokesman Brig. Gen. Daniel Justin said over the phone.

Earlier, local media reports blamed suspected members of armed opposition group loyal to ex-vice president Riek Machar for the attack.

The ambush is the latest in the series of similar attacks in the South Sudan’s southern region of Equatoria, where an economically vital road connects the capital Juba with northern Uganda and the wider East Africa region.

South Sudan descended into chaos in December 2013 following a political dispute in the ruling Sudan People’s Liberation Movement (SPLM) between President Salva Kiir and his former deputy Riek Machar led to fighting, mostly along ethnic lines.

The conflict has killed tens of thousands, displaced over 3 million, and put 6 million at risk of starvation.