Conakry - Guinea, Liberia and Sierra Leone announced an isolation zone sealing off the epicentre of the world's worst-ever Ebola outbreak, where the three countries meet.
"We have agreed to take important and extraordinary actions at the inter-country level to focus on cross-border regions that have more than 70% of the epidemic," said Hadja Saran Darab, the secretary-general of the Mano River Union bloc grouping the West African nations.
"These areas will be isolated by police and military. The people in these areas being isolated will be provided with material support."
The announcement came at the end of an emergency summit, also attended by Ivory Coast and the World Health Organisation, to launch a $100m response to an epidemic which has killed more 700 people.
"The healthcare services in these zones will be strengthened for treatment, testing and contact tracing to be done effectively.
"Burials will be done in accordance with national health regulations. We agreed to provide our health personnel with incentives, treatment and protection so they could come back to work."
Darab did not outline the exact area to be part of the isolation zone, but the epicentre of the outbreak spreads from Kenema in eastern Sierra Leone to Macenta in southern Guinea, almost 300km away.