The family of a journalist who was killed while covering a rebel offensive in South Sudan have called on South Sudan government to investigate circumstances surrounding their son’s death.

Christopher Allen, a freelancer, was killed in August 2017 while covering a rebel assault in Kaya near the border with Uganda.

During a vigil outside the South Sudan Embassy in Washington DC on Wednesday, the parents of the slain journalist met South Sudan Ambassador to US Philip Jada Natana and demanded for an inquiry into the killing of Mr Allen.

However, the South Sudanese diplomat said that the government is not accountable for Mr Allen’s death.

“We tried as a government to investigate, but the fact remains that for a long time, we were not able to complete the investigation,” Mr Natana  was quoted as saying by the VOA.

“Allen entered South Sudan through its southern border without proper documents, Jada said. He didn't come through the main town and through the main airport. Because then that becomes our responsibility once he enters,” he added.

The government says that Mr Allen had been embedded with SPLM-IO rebels at the time of his death.

He is the first foreign journalist killed in the South Sudan conflict.

Conditions for journalists in the war-torn state remain difficult with several journalists quitting the profession for fear of persecution and their lives.

Others fled to exile for similar reasons with several media houses remaining shut.