A rebel spokesman said the Kenyans were freed after an insurance company paid more than $100,000 (£71,620) in compensation for the death of a civilian killed when their plane hit the ground.

After more than a month in captivity, Captain Pius Frank Njoroge and co-pilot Kennedy Shamalla are reported to have arrived safely in the the South Sudanese capital Juba. A spokesman for the Kenyan foreign ministry told the BBC the two men would return to Kenya later today.

Rebels seized the pair early last month when their plane crashed in the Upper Nile region, reportedly killing a woman and livestock on the ground. The rebels had initially demanded a payment of more than $200,000 but agreed a compromise after negotiations with Kenyan officials.

A rebel spokesman insists the payment was not a ransom, but compensation for the deaths.

Kenyan pilots flying cargo and commercial operations to South Sudan had threatened to strike in support of their colleagues as the negotiations dragged on.