UN Secretary-General Ban Ki-moon says as long as there is one Ebola case in West Africa "all countries are at risk", and has urged nations to support the final battles to wipe out the disease in Sierra Leone and Guinea.
"We are on the home stretch now and what happens now is critical," the UN chief told a General Assembly meeting on efforts to end the Ebola epidemic.
The disease has killed more than 11,100 people mainly in Liberia, Sierra Leone and Guinea since it was first reported in March 2014.
Liberia, once the worst affected country, is now Ebola free, but Ban warned that in Sierra Leone and Guinea "the battle has not yet been won", and "any lapse in vigilance could allow the virus to spread".
Dr David Nabarro, the UN Ebola chief, told the assembly that the priority is to ensure the outbreak ends as soon as possible.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
He said that could take several weeks or a number of months.
"But everybody should be ready in case the disease recurs and needs to be controlled, especially in the coming 12 months," he said.
Ban said he will convene an International Ebola Recovery Conference in New York on July 10 to mobilise resources to start early recovery in Liberia, Sierra Leone and Guinea.
"We must also translate lessons learned from this Ebola outbreak into stronger national and international systems to prevent and respond to health crises," he said.
Last week, the World Health Organization's decision-making body examined how the response could have been improved to reduce suffering, deaths and other consequences including serious economic damage.
Ban has also commissioned a high-level panel on improving the Global Response to Health Crises led by Tanzania's President Jakaya Kikwete.
