US journalist Christopher Allen who was killed on Saturday is the tenth journalist to have been murdered in South Sudan since 2012. Picture: War Zone Freelance Project

Johannesburg - The Committee to Protect Journalists (CPJ) has called for an independent investigation into the circumstances surrounding the death of US freelance reporter and photographer Christopher Allen while covering the conflict in South Sudan.

Allen was killed on Saturday.

"CPJ called for an independent investigation into the circumstances surrounding Allen's death, and urged authorities to respect all journalists' status as civilians," said Angela Quintal, CPJ Africa Program Coordinator, in a statement issued late Tuesday.

Quintal said the committee was "deeply troubled" by reports that a South Sudanese army spokesman has denied that Allen, who was killed while covering the conflict in that country on August 26, was deserving of "civilian status". 

CPJ said South Sudan's army, a rebel spokesman, and the US embassy in the capital Juba confirmed Allen was killed during fighting between government and rebel forces in Kaya, near the borders with Uganda and the Democratic Republic of Congo. 

The CPJ said it was told by Col. Lam Paul Gabriel, the rebel's deputy spokesman, that Allen had been embedded with opposition forces for two weeks.

At a press conference on Tuesday South Sudan army spokesman, Lul Ruai Koang, said journalists who enter the country with rebel forces will not be protected. He said such a move was synonymous with "attacking" South Sudan.  

"Taking photographs and reporting events is not attacking. It is journalistic work done by civilians, who are protected under international law," said Quintal, who is based in New York. 

"We call for a credible, independent investigation into the killing of Christopher Allen so that those responsible can be held to account."

The CPJ said a man only identified as "Gabriel" who it said was with rebel forces, claimed South Sudanese soldiers deliberately targeted Allen for taking pictures of the fighting. He, however, offered no evidence when asked to back up this claim. 

"Gabriel said the rebels failed to recover his body because of heavy fire, but did get the journalist's camera and bag," the CPJ said.

In an interview with CPJ, Koang denied that the army deliberately targeted Allen.

The CPJ said South Sudan deputy army spokesman Col. Domic Chol Santo claimed the army had no way of identifying Allen as a journalist until his body was recovered. He said the army was looking into Allen's "illegal" entry into South Sudan. He also said the army had no immediate plans to investigate the killing.

Apart from confirming Allen's death, the US embassy did not respond to any additional questions, including those on the repatriation of Allen's body, and his migrant status in South Sudan. 

The embassy said it was still in the "process of obtaining all information related to this situation."

A civil war has been raging in South Sudan since 2013, displacing millions, and leaving tens of thousands dead in its wake. 

CPJ research suggests that in response to coverage of the fighting, South Sudan authorities have closed and obstructed access to news outlets, arrested journalists, and expelled reporters.