The deadly Ebola virus has spread from southern Guinea to the capital Conakry, The United Nations Children's Fund says.
At least 59 people were reported killed by the virus in the West African nation, where health officials say the outbreak has reached epidemic proportions.
"In Guinea, a country with a weak medical infrastructure, an outbreak like this can be devastating," UNICEF's Guinea representative Mohamed Ag Ayoya said on Sunday.
Guinea's Ministry of Health registered almost 100 infections since the virus was first reported last month, according to Radio France Internationale.
The southern districts Macenta, Kissidougou and Gueckedou, which border Sierra Leone, had been particularly affected by the outbreak, said Sakoba Keita, the head of the health ministry's prevention unit.
Three of 12 virus samples sent to France had been confirmed as Ebola, according to Keita.
Ebola is one of the most contagious viral diseases known, often resulting in death. The virus cannot be prevented with a vaccine and is untreatable with medication.
Medicins Sans Frontieres (MSF) launched an emergency medical intervention in the poverty-stricken West African nation's southern region.
MSF says that more than 30 tonnes of medical supplies are en route to Guinea. The organisation has a 24-member medical team on the ground and more staffers are scheduled to arrive in coming days.
"We have set up an isolation ward in Gueckedou," Dr Esther Sterk of MSF told American broadcaster Voice of America, saying an additional isolation ward will be set up in Macenta.
World Health Organisation officials were due to arrive on Sunday to conduct additional tests on site.
