The World Health Organization says a new case of Ebola has been confirmed in Liberia, days after saying the outbreak no longer qualifies as an international health emergency.

WHO said on Twitter Friday investigations are underway. It reiterated that Ebola is no longer an international health emergency, but flare-ups, at decreasing frequency, are expected. Liberia was declared free from transmission in January.

Flare-ups have occurred before in Liberia, and in Sierra Leone and Guinea, though health authorities say those are not linked to the original chain of transmission. WHO says Guinea has confirmed eight cases and seven deaths since late February.

The deadliest Ebola outbreak killed more than 11,300 people, mostly in Sierra Leone, Liberia and Guinea since December 2013. There are currently no known cases in Sierra Leone.