An outbreak of what tests suggest is pneumonic plague has spread to a second town in the Democratic Republic of Congo, according to a medical charity.
The plague outbreak is the largest in 50 years
Medecins Sans Frontieres (MSF) says it believes it has found a case in a second area in the north-east.
Thousands have fled the remote diamond mining town of Zobia since the disease first emerged at the end of last year.
At least 60 people have died so far. The plague affects victims lungs and is fatal if left untreated.
"People have been leaving Zobia. They were starting to panic - its contagious," MSF's Meike Steensens told BBC News from the city of Kisangani.
The outbreak began just four days after the diamond mine re-opened near Zobia, in Oriental province, north of the country's biggest city, Kisangani, a major trading centre on the Congo River.
Those who have died are all diamond miners. Another 350 miners have been infected.
MSF discovered the new case in the town of Buta after sending an emergency team of doctors to the area.
Final confirmation of the plague is expected next week, MSF say, but initial tests indicate that they are dealing with an outbreak of pneumonic plague.
An advance team of medical experts from the World Health Organisation (WHO) has already visited the area to confirm that people are infected with the plague.
Around 7,000 people worked at the mine. The WHO team will focus on trying to trace the 2,000 who have left since the start of the outbreak.
Bubonic plague is endemic in parts of Africa, including the DR Congo, but pneumonic plague, which occurs when bacteria infect the lung, has a very high fatality rate and is "invariably" deadly when left untreated, the WHO said.
Humans are generally infected with plague by rodents and fleas, but the pneumonic form of the disease can also be transmitted from person to person through respiratory droplets.