Gunmen kill four in raid on South Sudan's main highway

NAIROBI (Reuters) - Gunmen ambushed a convoy of buses traveling on a major highway in South Sudan on Wednesday, killing at least four passengers and wounding 10 others, police said.

The assailants attacked the convoy as it drove toward Juba on the road linking the South Sudanese capital Juba with Nimule, on the country's southern border with Uganda.

"Four civilians have so far been confirmed dead and 10 injured. We are yet to identify the attackers," a police spokesman said.

It is the second such attack along the highway since June, when an ambush killed 14 passengers and injured 35 others.

Rebels, who had claimed responsibility for that ambush, denied involvement in Wednesday's attack between the villages of Moli and Pageri.

South Sudan, the world's youngest country, has been mired in civil war since President Salva Kiir dismissed his deputy Riek Machar, in 2013.

A peace accord signed in April 2016, and backed by the United States and other Western nations, saw Machar return to the capital and share power with Kiir.

But the deal fell apart less than three months later and Machar and his supporters fled the capital.

Around 1.8 million people have fled the country since 2013, sparking what has become the world's fastest growing refugee crisis and largest cross-border exodus in Africa since the 1994 Rwandan genocide, humanitarian groups say.