MONROVIA (AFP) - An American cameraman who contracted Ebola in Liberia was evacuated on Sunday from Monrovia, a humanitarian source told AFP.

Ashoka Mukpo, 33, is the fourth American to contract Ebola in Liberia and had worked on humanitarian projects in the west African country for several years. He was hired by US television network NBC on Tuesday, but a day later put himself under quarantine as he came down with symptoms of the deadly virus.

The Nebraska Medical Centre, which is due to treat Mukpo, had announced on Twitter earlier that their patient would be arriving on Monday.

The hospital is among just a handful able to handle Ebola patients at this time, and has successfully treated a doctor who was also infected in Liberia.

NBC News president Deborah Turness said on Friday that the crew working with Mupko in Liberia were being closely monitored but were showing no symptoms. She added that they would be flown back on a chartered plane, and would then put themselves under quarantine for 21 days - the maximum incubation period for the virus.

Liberia is the hardest hit country by the current outbreak, accounting for about two-thirds of the total 3,338 deaths recorded in west Africa. The fever that the Ebola virus unleashes can fell its victims within days, causing severe muscle pain, vomiting, diarrhoea and - in many cases - unstoppable internal and external bleeding.