Ebola cases are continuing to rise "frighteningly quickly" in areas of Sierra Leone, an international campaign group has said.
The Africa Governance Initiative (AGI) found that in rural parts of the country the virus is spreading nine times faster than two months ago.
In Liberia, however, the rate of new cases appears to have slowed.
AGI's findings come after World Health Organization officials told the BBC the number of new cases is levelling off.
Though Sierra Leone's rural areas have been worst hit, the group says the spread of Ebola is also increasing in the capital Freetown - which is recording six times more cases per day compared to two months ago.
The virus has only started to slow in one region of Sierra Leone, Bombali in the country's north.
AGI - an organisation set up by former UK Prime Minister Tony Blair that operates in the affected countries - says it is not sure why cases are slowing in Liberia.
But the group says burial management has "improved significantly" in both Liberia and Sierra Leone. Half of all Ebola infections are thought to come from the bodies of victims.
AGI Chief Executive Nick Thompson said: "The picture is certainly changing but that's all we can say for sure at the moment.
"The pace of the spread in rural Sierra Leone shows we still have no time to lose."
On Friday 31 October the WHO said there had been 13,567 cases since the outbreak began, with 4,922 confirmed people to have died from the disease.