An angry crowd attacked a treatment centre in Guinea where staff from Medecins Sans Frontieres (MSF) were working to contain an outbreak of the deadly Ebola virus, forcing it to shut down, a spokesman for the medical charity said.

"We have evacuated all our staff and closed the treatment centre," Sam Taylor told Reuters news agency on Friday, adding that the attackers in Macenta, around 425km southeast of the capital Conakry, had accused MSF of bringing the disease to the southeastern town.

"We have the full support of the local leaders and we're working with the authorities to try and resolve this problem as quickly as possible so we can start treating people again," he said, declining to give further details of the incident.

More than 90 people have already died in Guinea and Liberia in what MSF has warned could turn into an unprecedented epidemic in an impoverished region with poor health services.

The outbreak in Guinea is the first time the disease, epidemics of which occur regularly in Central Africa, has appeared in the country. Infected patients initially went undiagnosed for several weeks before tests confirmed Ebola.

The latest outbreak originated in Guinea two months ago. Neighbouring Sierra Leone has since reported suspected cases while Liberia's government has confirmed the disease's presence there.

Gambia placed two people in quarantine although the Health Ministry has since said the cases were negative.

Senegal has closed its border with Guinea because of the outbreak.