West African nations including Mali, Ivory Coast, Senegal and Guinea Bissau should prepare for the arrival the deadly Ebola virus, the World Health Organisation said.
The WHO gave warning on Friday that the outbreak in Guinea, Sierra Leone and Libera - the worst recorded since the virus was identified - had the potential to spread to as travellers move between countries.
"We want other countries in West Africa to be ready - bordering countries, Ivory Coast, Mali, Guinea Bissau - to prepare themselves," said Pierre Formenty, a WHO medical official.
He said the UN health agency is not considering recommendation of travel or trade restrictions on the three countries already affected by the epidemic - Guinea, Sierra Leone and Liberia.
Meanwhile, Sierra Leone warned on Friday that it was a serious crime to shelter someone infected with the Ebola virus.
The Health Ministry, in a statement, lamented the fact that a number of patients had discharged themselves from hospital in Kenema district, where the outbreak is taking place, and gone into hiding.
The statement said that those interfering with the health teams would be punished.
The WHO warned on Thursday that dramatic steps were needed as the number of deaths from the virus continued to rise in Guinea, Liberia and Sierra Leone.
The WHO said it would convene a meeting of the health ministers from 11 countries in Accra, Ghana on July 2 and 3 to address the growing crisis.
Doctors Without Borders has described the outbreak as out of control. It has been linked to around 330 deaths in Guinea, Sierra Leone and Liberia.