New York's JFK airport was set to roll out health screenings for travelers arriving from Ebola-hit West African nations, as the death toll for ebola topped 4,000.
Passengers arriving from Liberia, Sierra Leone and Guinea will have their temperatures taken, be assessed for signs of illness and answer questions about their health and exposure history, the US Centers for Disease Control and Prevention (CDC) said.
Suspected cases could be barred from traveling further and referred to nearby hospitals if necessary, CDC said.
The health checks were one layer of protection put in place and CDC cautioned that no screenings are air tight.
"Exit screening might not find every person with Ebola, however, it does not have to be perfect to help reduce the spread of Ebola," it said in a statement.
The scaled-up measures come after the death on Wednesday of Thomas Duncan, the first person diagnosed with the disease outside Africa, who succumbed to the disease in a Texas hospital after being given an experimental drug.
The case sparked panic about the possible spread of the deadly virus in the United States, though President Barack Obama said the chances of a US Ebola outbreak were "extraordinarily low."
JFK was the first airport to implement the screenings, and four other airports -- Newark in New York, Chicago's O'Hare, Washington's Dulles and Atlanta international airport in Georgia -- are set to start the checks next week.
The screenings were not expected to clog arrival terminals, with only about 150 passengers per day set to be examined at all ports of entry, CDC director Tom Frieden told CNN.
Around 50 percent of arrivals from the three West African countries pass though New York's JFK airport, a major travel hub.
Together, all five airports account for 94 percent of all travellers coming into the United States from Guinea, Liberia and Sierra Leone, the worst-affected countries.
CDC said it already has 20 quarantine stations at airports throughout the United States.