A haemorrhagic fever that has killed 16 people and infected more than 50 others in Uganda has been confirmed as the deadly Ebola virus.
The casualties are all in the region of Bundibugyo, on the border with the Democratic Republic of Congo.
DR Congo has been battling for five months to contain an Ebola outbreak close to its border with Angola.
Symptoms of the epidemic include high temperature, bloody diarrhoea and visible haemorrhaging.
There is no known cure for Ebola, which is fatal in around 80% of cases.
Ugandan health officials originally suspected that the Marburg virus was responsible for the deaths, but laboratory testing has shown it to be Ebola.
The authorities say they are taking steps to isolate existing cases.
"From the beginning we've been isolating cases... but we can't say it's contained," Reuters news agency quotes Dr Sam Okware, head of Uganda's haemorrhagic fever task force, as saying.
"There may be other people in those villages unknown to us," he said.
The virus is thought to be transmitted through the consumption of infected bush meat and can also be spread by contact with the blood secretions of infected people.
Some 174 people have died in DR Congo but only 13 of these have been confirmed as having Ebola.