President Barack Obama has called the West Africa Ebola outbreak "a threat to global security" as he announced a larger US role in fighting the virus.
"The world is looking to the United States," Mr Obama said, but added the outbreak required a "global response".
The measures announced included ordering 3,000 US troops to the region and building new healthcare facilities.
Ebola has k**ed 2,461 people this year, about half of those infected, the World Health Organization said.
The announcement comes as UN officials have called the outbreak a health crisis "unparalleled in modern times".
The spread of the disease means the funds needed to fight the outbreak have increased 10-fold in the past month, the UN's Ebola co-ordinator said, saying it needs $1bn (£614m) to fight the outbreak.
'Ma**ive surge needed'