Liberia confirmed a third new case of the deadly Ebola virus on Thursday, as the disease re-emerges nearly two months after the outbreak was declared over in the West African nation, a senior health official said.

Liberia, where 4,800 people have died out of the 11,200 killed in the West African Ebola outbreak, was declared Ebola-free on May 9 even as the disease has continued to infect new victims in neighboring Sierra Leone and Guinea. But Liberia's success story has been undermined this week by the discovery of new cases.

"We have, as of yesterday, three confirmed cases. One expired, who was the 17-year-old boy ... The two live cases are 24 years old and 27 years old. They are stable," Deputy Health Minister Tolbert Nyenswah said on Thursday.