The death toll from the Ebola outbreak tearing through West Africa has passed the 1,500 mark while the number of cases has soared past 3,000, the World Health Organization has said.
As of 26 August, 1,552 people had died from the murderous epidemic that reared its head at the beginning of the year, while 3,062 had become infected, the UN's health body said.
On August 20, the toll stood at 1,427 deaths out of 2,600 cases.
Earlier, a doctor in Nigeria's oil industry hub of Port Harcourt died from Ebola fever, after he was infected by a man linked to the first case in Africa's most populous country, the country's Health Ministry has said.
Health Ministry spokesman Dan Nwomeh said the doctor had treated a primary contact of Patrick Sawyer, the Liberian who brought Ebola to Lagos.
Port Harcourt lies at the heart of Nigeria's two million barrels per day oil industry and is a hub for expatriate workers in major international oil companies.
Ebola epidemic set to get worse
The head of the US's top public health body said the Ebola epidemic in Liberia is set to get worse and many cases of the deadly disease are not included in the official tally.
"The cases are increasing. I wish I did not have to say this, but it is going to get worse before it gets better," Tom Frieden, the director of the Centers for Disease Control and Prevention, told a news conference in Monrovia.
"The world has never seen an outbreak of Ebola like this. Consequently, not only are the numbers large, but we know there are many more cases than has been diagnosed and reported," he said.
Liberia has been hardest-hit by the epidemic now raging through west Africa, with 624 deaths and 1,082 cases since the start of the year.
The WHO believes its count is likely far too low, due in part to community resistance to outside medical staff and a lack of access to infected areas.
With Liberia struggling to contain the spread of the virus, Mr Frieden met the country's leader, President Ellen Johnson Sirleaf, on Monday, to discuss ways to combat the epidemic.
He said there was a need for "urgent action" as he called on Liberians "to come together" to fight the epidemic, which has brought the country to its knees.
"It is not going to be easy... (but) one good thing about Ebola is that we know how to stop it. There are misconceptions but we know how it spreads," he said.
He asked people not to touch sick relatives and to make sure they stayed out of contact with bodily fluids -- such as sweat and blood -- which can transmit the virus.
Ebola, a deadly form of haemorrhagic fever, causes fever, vomiting, diarrhoea and internal bleeding.
The virus has been fatal in just over half of cases in the current outbreak, the largest on record.