President Barack Obama has warned of a “potential threat to global security” if Ebola-stricken West African countries break down, as he announced 3,000 US troops would be sent to the region.
“If the outbreak is not stopped now, we could be looking at hundreds of thousands of people affected, with profound economic, political and security implications for all of us,” Mr Obama said at the Centers for Disease Control and Prevention in Atlanta, Georgia.
The virus has claimed nearly 2,500 lives out of almost 5,000 cases this year – mostly in Liberia, Sierra Leone and Guinea.
Outlining measures to prop up health services in areas overwhelmed by the epidemic, Mr Obama said: “It’s spiralling out of control, it’s getting worse.”
But he stressed the chances of an outbreak in the US were “extremely low”.
Under the plan, engineers, medical personnel and other service members will build 17 treatment centres in West Africa, each with 100 beds.
The US also aims to train 500 medical staff a week and establish a military control centre for co-ordinating the relief effort.
The cost of the aid is expected to be $500m (£308m).
It is expected to take two weeks to get US personnel on the ground.
Earlier on Tuesday Mr Obama welcomed Dr Kent Brantly, an American missionary who caught ebola in Liberia and made a full recovery in the US, to the White House.
Four Americans have been or are being treated for ebola in the US after evacuation from Africa.
The World Health Organization warned the number of Ebola cases could start doubling every three weeks, threatening a “human catastrophe”.
The UN health agency’s assistant director General Bruce Aylward said the crisis was “unparalleled in modern times”.
Doctors Without Borders president Dr Joanne Liu told a UN special briefing on Ebola in Geneva: “The window of opportunity to contain this outbreak is closing.
“We need more countries to stand up, we need greater deployment, and we need it now.”
In addition to the US response, the WHO said China has promised to send a 59-person medical team to Sierra Leone to help fight the epidemic.
The UK is planning to set up an Ebola clinic in Sierra Leone, while Cuba has promised to send some 160 health workers to the country.
UN Secretary-General Ban Ki-moon will launch a “global response coalition” in New York on Thursday.
The virus, which has also reached Nigeria, Senegal and Democratic Republic of Congo, is spread through direct contact with the bodily fluids of sick patients. There is no vaccine or approved treatment.
The US ambassador to the United Nations, Samantha Power, has called for an emergency meeting of the Security Council, warning the virus could “set the countries of West Africa back a generation”.
US efforts will include medics and corpsmen, engineers to help build treatment facilities and logistics specialists to assist in patient transportation.
