The World Health Organization (WHO) has warned that Ebola is now entrenched in the capital cities of all three worst-affected countries and is accelerating in almost all settings.
WHO deputy head Bruce Aylward warned that the world’s response was not keeping up with the disease in Guinea, Liberia and Sierra Leone.
The three countries have appealed for more aid to help fight the disease.
The outbreak has killed more than 3,860 people, mainly in West Africa.
More than 200 health workers are among the victims.
Speaking on Thursday, Mr Aylward said the situation was worse than it was 12 days ago.
“The disease is entrenched in the capitals, 70% of the people affected are definitely dying from this disease, and it is accelerating in almost all of the settings,” he said.
The medical charity Medecins Sans Frontieres (MSF) reported a sharp increase of Ebola cases in the Guinean capital, Conakry, dashing hopes that that the disease was being stabilised there.
Sepaking to the BBC on Friday, MSF President Joanna Liu called for urgent international action.
“We’re not winning the battle,” she said.
“To get ahead of the game we’re going to need to deploy much more massively than what we have done so far.”
At least one in 20 of those killed in the latest outbreak were medical workers, she said.
The US emphasis in Liberia is on providing treatment for sick health workers
Meanwhile in Spain, seven more people are being monitored in hospital for Ebola.
They include two hairdressers who came into contact with Teresa Romero, a Madrid nurse looked after an Ebola patient who had been repatriated from West Africa.
Ms Romero is now very and reported to be at serious risk of dying.