Ebola is still spreading quickly in western Sierra Leone and deep in Guinea's forested region, a senior UN official said on Tuesday.
More foreign health workers are needed to combat the epidemic, especially in Sierra Leone where treatment centres are still opening and need expert staff, said David Nabarro, the UN Secretary General's special envoy for Ebola.
The death toll from the Ebola outbreak in West Africa has risen to 6,331 in the three worst hit countries, with Sierra Leone overtaking Liberia as the country with the highest number of cases, the World Health Organization says.
"We know the outbreak is still flaming strongly in western Sierra Leone and some parts of the interior of Guinea. We can't rest, we have to still push on," said David Nabarro, the U.N. Special Envoy on Ebola.
More treatment centres are opening in Sierra Leone but they need additional trained staff, he told a news briefing.
"We don't yet have the full number of functioning treatment centres and places where people who are ill can be kept away from others," he said.
"We are anticipating several hundred beds to come on stream in the next few weeks, and that will lead to the situation calming down."
Treatment centers are still opening in Sierra Leone and need expert staff, he told a news briefing in Geneva.
The deadly virus is spreading particularly in Sierra Leone's capital of Freetown and Port Loko "where there is a need for a much more intense response", said Nabarro, a veteran public health expert.
"The increase in transmission in western Sierra Leone is a reflection of the fact that communities there have yet to fully embrace the outbreak and to take action to avoid infection themselves," he added.
The second "troublesome" area is the northern part of Guinea's interior, a region known as Guinea Forestiere, he said.
"We have been working very closely with Mali to try to make sure if cases perchance cross the border that they can be dealt with very quickly."
"We do need to keep making it clear that people are needed and needed urgently ... Every day we wake up and realize the enormity of the job ahead," Nabarro said.
Mali has reported eight Ebola cases, six fatal, to date.