President Obama, flanked by American medical personnel who have either recently returned from fighting Ebola in West Africa or are en route to the region, shot back Wednesday at critics who have said the United States should impose further restrictions on travel from nations affected by the virus.

"When I hear people talking about American leadership and then are promoting policies that would avoid leadership and have us running in the opposite direction and hiding under the covers, it makes me a little frustrated," he told a crowd gathered in the East Room of the White House. "We’re at our best when we are standing up and taking responsibility, even when it requires us making sacrifices – especially when it requires us making sacrifices."

"So I put those on notice who think that we should hide from these problems: that’s not who we are, that’s not who I am, that’s not who these folks are," he said. "This is America, and we do things differently."

Obama said that the United States should be treating returning medical personnel like "heroes" rather than stigmatizing them upon their return.

"Like our military men and women deploying to West Africa, they do this for no other reason than their own sense of duty, their sense of purpose, their sense of serving a cause greater than themselves," the president said. "And we need to call them what they are, which is American heroes. They deserve our gratitude, and they deserve to be treated with dignity and with respect."

Kent Brantly, the missionary doctor for the group Samaritan’s Purse who became infected with Ebola in Liberia this summer but recovered after he received an experimental drug and was evacuated to Atlanta for treatment, introduced the president.

Brantly praised the medical personnel from Guinea, Liberia and Sierra Leone who have been battling the epidemic, saying they "have fought with valiant effort against this menace, but they need the help of the international community to turn the tide of this epidemic."

Obama echoed that theme, saying the United States should not do anything to hamper the flow of its health workers to the countries hardest hit by the deadly virus. The Centers for Disease Control have issued monitoring guidelines "tailored to the unique circumstances of each health care worker. But we have to keep in mind that if we're discouraging our health care workers, who are prepared to make these sacrifices, from traveling to these places in need, then we're not doing our job in terms of looking after our own public health and safety."

"If we are not dealing with this problem there, it will come here," he said.

The president also warned that there may be future Ebola infections in the United States.

"And I want America to understand: The truth is that until we stop this outbreak in West Africa, we may continue to see individual cases in America in the weeks and months ahead, because that's the nature of today's world," he said. "We can't hermetically seal ourselves off. The nature of international travel and movement means that the only way to assure that we are safe is to make sure that we have dealt with the disease where it -- right now, it is most acute."

 "So yes, we are likely to see a possible case elsewhere outside of these countries, and that's true whether or not you adopt a travel ban, whether or not you adopt a quarantine, it’s the nature of diseases," he said.

The room's front row was filled with senior administration officials spearheading the federal Ebola response, including its coordinator Ron Klain, the president's homeland security and counterrorism adviser Lisa Monaco; his national security adviser Susan Rice; Health and Human Services Secretary Sylvia M. Burwell; Anthony Fauci, who heads the National Institute of Allergy and Infectious Diseases; U.S. Agency for International Development administrator Raj Shah and White House domestic policy director Cecilia Muñoz.

The president pointed to some positive signs in West Africa, including the fact that safe burial practices have doubled in Monrovia and that his U.N. ambassador Samantha Power told him in the Situation Room Wednesday afternoon that the United States is setting up Ebola treatment units ahead of schedule, and is already setting up supply lines.