The number of confirmed Ebola cases in Uganda has risen to nine from three, the country's health ministry said.

The East African country declared an outbreak of the severe, often-fatal viral infection late last month.

The latest outbreak is being driven by the Sudan strain of the virus, for which there is no approved vaccine.

Uganda's health ministry said in a statement late on Monday that of the nine confirmed cases one person had died, seven were being treated in a hospital in the capital Kampala and one was in a hospital in the eastern city of Mbale, near the Kenyan border.

All eight patients are in a stable condition, and 265 contacts of the confirmed cases have been placed under quarantine, the ministry said.

Uganda has launched a trial vaccination programme against the Sudan strain of Ebola, the World Health Organization said this month.

Existing vaccines are for the Zaire strain of Ebola, which was behind recent outbreaks in neighbouring Democratic Republic of Congo.