President Barack Obama urged Americans not to give in to Ebola hysteria, stressing that the two cases contracted in the US were not an epidemic or an outbreak.
Barack Obama has also ruled out imposing a travel ban on Ebola-hit countries of West Africa.
He said isolating an entire region, a move urged by some Republicans, would make the situation worse.
The Ebola virus has killed about 4,500 people in Guinea, Sierra Leone and Liberia, according to the UN.
Barack Obama said the best way to tackle the disease was at its source, before it spreads.
“Trying to seal off an entire region of the world, if that were even possible, could actually make the situation worse,” he said.
“It would make it harder to move health workers and supplies back and forth.
“Experience shows that it could also cause people in the affected region to change their travel, to evade screening, and make the disease even harder to track.”
Barack Obama stressed that the US was not in the middle of an outbreak or an epidemic and urged Americans to stay calm.
However, the New York Times has reported that the president was furious with his aides over an inadequate response to the disease.
The newspaper said medical officials had given information that turned out to be wrong, local guidance was inadequate and categories of threats were unclear.
Some 60 Republicans in the House of Representatives have informally said they would support a travel ban, according to an unofficial count on the Hill website.
They were joined by a handful of Democrat representatives and a small number of Republicans in the Senate.
Republican House Speaker John Boehner, who supports travel restrictions, has hinted that he may propose a vote on the issue.
Several US airports have begun screening for Ebola, despite experts saying such moves were unlikely to have an impact.
Two American nurses contracted the virus after treating Liberian Thomas Eric Duncan, who subsequently died of the disease at a hospital in Dallas.
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