UNITED NATIONS : The United Nations has set a goal of stopping the spread of the world’s worst-ever Ebola outbreak within six to nine months, UN chief Ban Ki-moon said Friday.

After meeting with top health officials, Ban said the “next few weeks will be crucial” to step up international efforts and called on countries to contribute to a $600 million appeal for supplies to West Africa. “The goal is to stop Ebola transmission in affected countries within six to nine months, and to prevent the international spread of the virus,” said Ban.

He announced the creation of an Ebola crisis center to be the focal point for the international strategy to combat the virus that has left about 1,900 dead in Guinea, Liberia and Sierra Leone.

Ban called on countries to join in a “massive surge in assistance” to West Africa by sending more doctors, nurses, beds, trucks, equipment and other vehicles. “We are together today to send out an international rescue call,” said the UN secretary general.

 following talks with World Health Organization director Margaret Chan and UN coordinator for Ebola David Nabarro at UN headquarters in New York.

The United Nations scaled up its anti-Ebola campaign after the international medical group Medecins Sans Frontieres this week raised alarm by declaring that the world was “losing the battle” to contain Ebola. Ban said the number of cases was “rising exponentially” and warned that “the disease is spreading far faster than the response.” In the worst affected countries — Guinea, Sierra Leone and Liberia — health officials have documented a total of 3,685 cases of which 1,841 have resulted in death.

The tropical virus can fell its victims within days, causing severe fever and muscle pain, weakness, vomiting and diarrhea — in some cases shutting down organs and causing unstoppable bleeding. No widely available vaccine or treatment exists, but health experts are looking at fast-tracking two potential vaccines and eight treatments including the drug ZMapp.