Health officials in Mali say they are investigating three suspected cases of Ebola amid an outbreak in two other West African countries.

In a government statement released late Thursday, Malian officials said they were awaiting test results from samples sent to the United States. It said the three patients have been placed into isolation for observation.

An Ebola outbreak was confirmed late last month in Guinea, where at least 84 people have died. Two confirmed deaths also have been reported in neighboring Liberia.

Ebola is one of the deadliest diseases on Earth, killing up to 90 percent of those who contract the strain of the virus found in Guinea.

It’s the first time Ebola has been reported in the affected countries; other outbreaks have taken place in Central Africa.