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'