Cases of hemorrhagic fever were reported in an area of Congo that is facing an Ebola epidemic as far back as December and the first deaths were reported in January, a spokesman for the World Health Organization said in the capital Kinshasa on Thursday.

The health ministry said on Tuesday that at least 17 people had died in an area of northwestern Democratic Republic of Congo where health officials have now confirmed an outbreak of Ebola, but did not give a time frame. Only two cases have been confirmed, by a laboratory in Kinshasa.

A timespan as long as five months since the first infection would be alarming, since it would give the virus a head start in infecting a lot more people before any action was taken to contain it.

This is the ninth time Ebola has been recorded in the vast, forested central African nation since it was first identified near the eastern Ebola river in the 1970s. It comes less than a year after an outbreak which killed eight people.

"According to our early information, the cases have been reported since December and the first deaths were reported in January, but the link between the deaths and the epidemic has not yet been established," WHO Congo spokesman Eugene Kabambi told Reuters.

The health ministry said on Thursday it had dispatched a team of 12 experts to the area to try to trace new contacts of the disease, identify affected villages and provide resources to combat the epidemic.

Ebola is best known and most feared for the internal and external bleeding it can cause in its victims, owing to damage done to blood vessels. Victims often die of shock but symptoms can be vague, including fever, muscle pain, diarrhoea and nausea.

The worst Ebola epidemic in history ended in West Africa just two years ago after killing more than 11,300 people and infecting 28,600 in Guinea, Sierra Leone and Liberia.