GENEVA (AFP) - The murderous Ebola outbreak ripping through west Africa is taking a devastating toll on children, with some 2,000 orphaned in worst-hit Liberia alone, the United Nation's children's agency said on Friday.

"It is really quite heartbreaking to see the effect that this (outbreak) has on children and their families," said Ms Sarah Crowe, head of Unicef's crisis communication in Liberia.

Speaking to reporters in Geneva via audio link from Monrovia, she said that it's "looking possibly at 2,000 children who have been left without parents" in Liberia alone. "Children are seeing their family members and relatives taken away by people in effectively astronaut suits,... and the effect is deeply distressing," she said.

Children who have lost family members to Ebola meanwhile often face "deep stigma", she pointed out, meaning they are often rejected by the community and forced to roam the streets without proper parental care, shelter or food. According to Unicef, around 20 per cent of children with family members who have died from Ebola in Liberia are under the age of two.

The agency was working to find new ways of ensuring that these children receive care, including asking Ebola survivors, who become immune to the virus, to take on the role of caregivers.

The worst-ever outbreak of Ebola has now killed more than 2,400 people in four west African countries out of double as many infections, the World Health Organisation (WHO) said Friday.

Liberia has born the brunt of the outbreak, which began at the beginning of the year, alone accounting for more than half of the deaths.

The country is facing "tremendous strain" on its already fragile health system, which had been on a slow road to recovery after 14 years of civil war when the outbreak began.

WHO chief Margaret Chan stressed on Friday that there is not a single bed left to treat Ebola patients in Liberia.

And Ms Crowe pointed out that the focus on Ebola meant other child-killing diseases like measles, pneumonia and diarrhoea were being sorrowfully neglected.

"There are great concerns about child mortality," she said, lamenting that "we're going to feel the impact of this for a long while to come".

At the same time, schools were closed and children are being told not to touch or play with others, which "not a natural human reaction", she said.

"Children are living in a sort of twilight zone," she said, insisting that "there really needs to be a massive scaling up of support".