The US envoy to the United Nations criticised the level of international support for nations hit by Ebola as she began a tour Sunday of west African nations struggling with the disease.
Samantha Power said before arriving in Guinea that too many leaders were praising the efforts of countries like the United States and Britain to accelerate aid to the worst-affected nations, but were doing little themselves.
"The international response to Ebola needs to be taken to a wholly different scale than it is right now," Power told NBC News before boarding her plane.
She said many countries "are signing on to resolutions and praising the good work that the United States and the United Kingdom and others are doing, but they themselves haven't taken the responsibility yet to send docs, to send beds, to send the reasonable amount of money".
After Guinea, Power will travel to Sierra Leone and Liberia. Those three nations account for the vast majority of the 4,922 deaths from the virus.
She will also visit Ghana, where the UN mission fighting Ebola is based, before meeting EU officials in Belgium.
More than 10,000 people have contracted the Ebola virus, according to the latest World Health Organization figures.
Another west African country, Mali, was scrambling to prevent a wider outbreak after a two-year-old girl died from her infection following a 1,000-kilometre (600-mile) bus ride from Guinea. She was Mali's first recorded case of the disease.
'Feel like a criminal'
An American nurse who was placed in quarantine after caring for Ebola sufferers in Sierra Leone has complained she was made to feel "like a criminal".
Kaci Hickox, who later tested negative, was the first person to be placed under a mandatory 21-day quarantine for medical staff returning to parts of the US who may have had contact with Ebola patients in west Africa.
The new rules took effect in New York and New Jersey on Friday, the same day Hickox returned.
"This is not a situation I would wish on anyone, and I am scared for those who will follow me," Hickox wrote in The Dallas Morning News.
"I am scared about how health care workers will be treated at airports when they declare that they have been fighting Ebola in west Africa. I am scared that, like me, they will arrive and see a frenzy of disorganization, fear and, most frightening, quarantine."
In response, Ambassador Power expressed concern that the new quarantine policies were "haphazard and not well thought out".
She said there was a danger the new regulations could set back the fight against the virus.
"We cannot take measures here that are going to impact our ability to flood the zone" with health workers, Power said.
"We have to find the right balance between addressing the legitimate fears that people have and encouraging and incentivizing these heroes."
President Barack Obama told Americans Saturday they must be "guided by the facts, not fear" after a 33-year-old US doctor returned from Africa became the first Ebola case in New York City.
Australian authorities said Sunday a teenage girl was in isolation in hospital and undergoing tests for Ebola after she developed a fever following her arrival from Guinea 11 days ago.
The 18-year-old, who arrived in Australia with eight other family members, had been in home quarantine in Brisbane before she developed a "raised temperature" overnight.
The WHO has warned the situation in Mali is an "emergency" after a girl died from Ebola following a bus ride from Guinea to Mali with her grandmother during which she was said to have showed contagious symptoms.
But Mali President Ibrahim Boubacar Keita tried to calm fears.
"We are doing everything to prevent panic," he said in an interview with French radio on Saturday, but he admitted that landlocked Mali could never "hermetically seal" itself.
Mauritania meanwhile reinforced controls on its border with Mali, which effectively led to the frontier being closed, according to local sources.
US Major General Gary Volesky took over Saturday as commander of the 700-man American military mission to combat Ebola in west Africa.
The mission is due to open a 25-bed hospital for health workers in the Liberian capital Monrovia in early November.