The Biden administration on Tuesday said everything possible must be done to stop Ebola outbreaks in the African nations of Guinea and Democratic Republic of Congo before they become large epidemics.

"We cannot afford to take our foot off the gas – even as we battle Covid, we must ensure capacity and financing for health security worldwide," White House press secretary Jen Psaki said in a statement.

Congo in central Africa on Sunday confirmed four cases since September 7 and Guinea in west Africa had seven confirmed cases and three deaths.

National security adviser Jake Sullivan on Tuesday spoke with the ambassadors of Guinea and Congo as well as Guinea neighbours Sierra Leone and Liberia to convey US willingness to help, according to Psaki.

The World Health Organization, already deep in a fight against the global coronavirus pandemic, is working to learn more about the origins and strains of the Ebola outbreaks.

The disease, which killed more than 11 000 over 2-1/2 years starting in 2013, now poses a regional risk requiring exceptional vigilance, the World Health Organization warned on Monday.