Megyn Kelly tonight pressed CDC Director Dr. Thomas Frieden on the government’s response to the Ebola threat.

Kelly reminded Frieden that he assured the public that the U.S. would stop Ebola in its tracks. But now, Ebola patient Thomas Eric Duncan has died, and one of the nurses that cared for him also has Ebola, though Frieden said health care workers would be trained.

“The American public looks at you and says, ‘Why should we trust you, and why should we trust the administration when Barack Obama told us we are prepared if Ebola reaches our shores and that the medical personnel would be adequately trained?’” Kelly said.

Frieden admitted that it’s “deeply troubling” that a nurse has contracted Ebola.

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Still, he pledged, “We will stop the chains of transmission, I have no doubt about that. But it’s not going to be easy, and in West Africa, it’s not going to be quick.”

Kelly asked why the U.S. is not putting a travel ban in place, and Frieden said the CDC has already recommended that nonessential travel to the region should be stopped.

When asked if he believes the chances of a U.S. Ebola outbreak are extremely low, Frieden said, “We will not have a large outbreak of Ebola in the U.S.”

“The Kelly File” host also asked Frieden for his response to those who call for his resignation – including Bill O’Reilly.

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“I’m focused on protecting Americans 24/7. I’m focused on stopping the outbreak in Africa and on preventing more Americans from becoming exposed if patients come here,” he said.

Watch the full interview above.