The Ebola outbreak in west Africa is moving faster than efforts to control it, the World Health Organisation (WHO) said.
Director-general of WHO Dr Margaret Chan claimed governments may need to impose restrictions on population movements and public gatherings in order to contain the deadly virus, which has killed 729 people.
An emergency committee will meet next week to decide if the crisis constitutes a "public health emergency of international concern".
Speaking to the presidents of Guinea, Liberia, Sierra Leone and Ivory Coast, Chan said the virus can be contained but the severity of the issue has outstripped their countries' capacity to respond.
Police may also have to be used to guarantee the safety of Ebola response teams, Chan added.
As it reaches seven months since the Ebola outbreak started we take a look at the timeline of events leading up to the spread of the virus.
More than 100 British personnel are arriving in Sierra Leone to combat the Ebola outbreak in West Africa. Here's what else the UK is doing.
A man has been filmed helping an Ebola patient onto a plane without wearing any protective equipment.