Sierra Leone says its death toll from the contagious Ebola virus has doubled in one week, with hopes of containing the outbreak fading.
Health ministry officials said at least 12 people had been killed by the deadly virus, up from six last week.
They say the confirmed deaths were in the east, near the border with Guinea - the epicentre of the outbreak that has killed more than 200 people this year.
There is no cure or vaccine for Ebola - one of the world's deadliest viruses.
The impoverished west African nation confirmed its first deaths from Ebola two weeks ago.
Resistance to treatment
Dr Amara Jambai, the director of disease prevention and control at Sierra Leone's health ministry, announced on Monday that the deaths in the east were mainly in the Kailahun district.
There are now 42 confirmed cases from 113 people tested, with new cases recorded in the northern district of Kambia, she added.
She said that the disease was spreading as local authorities were struggling to control the movement of people, according to Reuters news agency.
Guinea has been worst-affected, with some 328 cases - 193 of which have been confirmed by laboratory tests - and 208 deaths.
Ebola virus disease (EVD)
- Symptoms include high fever, bleeding and central nervous system damage
- Fatality rate can reach 90%
- Incubation period is two to 21 days
- There is no vaccine or cure
- Supportive care such as rehydrating patients who have diarrhoea and vomiting can help recovery
- Fruit bats are considered to be the natural host of the virus
The latest figures follow warnings by health authorities and aid agencies in West Africa that the deadly virus is continuing to spread in the region, with Ebola reported in areas where there had been no new cases in more than 40 days.
The World Health Organisation and Medecins Sans Frontieres say this could be down to the resistance of certain communities to medical aid, with some people refusing to go to hospital and others turning to traditional healers instead.
Ebola, a haemorrhagic fever, can kill up to 90% of those infected and is passed on through contact with the fluids of infected people or animals, such as urine, sweat and blood.
But people have a better chance of surviving if it is identified early and they receive medical attention.
In Liberia, there have been 12 suspected cases of Ebola, with nine deaths.