Africa's top public health agency and Congolese officials have raised concerns over $700 million in Ebola aid which is unaccounted for, and called on aid groups to provide more information about their finances.

This comes as the world's fastest-growing Ebola outbreak on record continues to outpace efforts, and the virus has spread into eight provinces in Congo and into neighboring countries, Kenya and Uganda.

The revelations renew long-standing questions about transparency and accountability in Congo, a country battered by decades of major epidemics, including repeated Ebola outbreaks.