Support for health workers and ensuring they have proper protective equipment and training is essential, WHO health security chief Keiji Fukuda told reporters.
"This outbreak really underscores the importance of having strong health systems," he said.
Despite the new measures, Fukuda acknowledged "the likelihood is that it will get worse before it gets better," adding that WHO was bracing to deal with the outbreak "at some level for some number of months."
Soldiers in Liberia's Grand Cape Mount province -- one of the worst-affected areas -- set up road blocks to limit travel to the capital Monrovia, as bodies reportedly lay unburied in the city's streets.
In Sierra Leone, which has the most confirmed infections, 800 troops were sent to guard hospitals treating Ebola patients. Two towns in the east of the country were put under quarantine and entertainment venues across the country were ordered shut.
In Nigeria -- where the outbreak has so far been minor compared to the other affected countries, with two dead and five others infected -- public sector doctors suspended a nearly five-week strike to help battle the deadly virus and prevent it from taking hold in Africa's most populous country.
As African nations struggled with the scale of the epidemic, the scientists who discovered the virus in 1976 have called for an experimental drug being used on two infected Americans to also be made available for African victims.
The two infected Americans, who worked for Christian aid agencies in Liberia, have shown signs of improvement since being given ZMapp, which is made by US company Mapp Pharmaceuticals.
Spain also flew home a 75-year-old Roman Catholic priest, Miguel Pajares, the first European victim of the epidemic, on Thursday. Officials said his condition was stable.
"If you have health systems, you have awareness, you are ready for it, this is something that you can stop," he stressed.
First discovered in 1976 and named after a river in what is now the Democratic Republic of Congo, Ebola has killed around two-thirds of those infected, with two outbreaks registering fatality rates approaching 90 percent. The latest outbreak has a fatality rate of around 55-60 percent.