UN Secretary General Ban Ki-moon has urged local communities in west Africa to strictly follow health regulations in the face of signs that traditional funerals are still spreading the disease.
Mr Ban arrived in Liberia at the start of a two-day tour of four nations struck by the worst ever outbreak of the deadly haemorrhagic fever, including Sierra Leone, Guinea and Mali.
The tour aimed to raise the profile of the efforts to fight Ebola and to thank the hundreds of organisations and thousands of health workers who have participated, he said.
"Our goal is to see the last case identified and cured," Mr Ban said.
"We would like to urge local communities that this is a temporary operation and we fully respect the cultural traditions but at this time it is important to abide by health protocols."
Traditional west African practices - such as washing the bodies of the dead by hand at funerals - have helped to spread the fever, which has no known cure.
The death toll from the nine-month-old epidemic rose to 6,915 as of 14 December, the World Health Organisation said on Wednesday.
The virus, which causes vomiting, diarrhoea and bleeding in its final stages, is spread by contact with the bodily fluids of the sick.
Rates of infection are rising fastest in Sierra Leone, which accounts for more than half of the 18,603 confirmed cases of the virus.
Infection is spreading rapidly around the coastal capital Freetown, where some aid workers say public information efforts have lagged.
Sierra Leone launched "Operation Western Area Surge" this week to contain the outbreak - with health workers passing street by street looking for the sick.
Medical charity Medecins Sans Frontieres (MSF) said it had opened two new Ebola treatment centres in Sierra Leone to cope with the rise in cases - in Freetown and the central town of Magburaka, bringing its total in the country to four.
"There is still a need to improve messaging about the disease. 70% of people in our Freetown treatment centre got infected at funerals," said Thierry Goffeau, MSF's emergency coordinator in Sierra Leone.