Speaking from the White House lawn on Tuesday, President Obama gave an update on efforts to stop the spread of the Ebola virus in West Africa and in the U.S. (AP)

This post has been updated.

President Obama said Tuesday his administration would only adopt Ebola policies that would not jeopardize the ongoing effort to contain Ebola in West Africa.

"We don’t just react based on our fears. We react based on facts and judgment and making smart decisions," he said in remarks Tuesday afternoon just before boarding Air Force One.

The president noted that he had just placed a call to members of the U.S. Agency for International Development's Disaster Assistance Response Team (DART), which has been on the ground in West Africa since the first week in August. "We know that the best way to protect Americans ultimately is going to stop this outbreak at the source," he said.

While Obama did not explicitly criticize the governors of New York and New Jersey for imposing a quarantine on returning medical workers from Ebola-affected countries, he made it clear he disagreed with the decision.

"So we don’t want to discourage our health care workers from going to the front lines and dealing with this in an effective way," he said. "Our medical teams here are getting better and better prepared and trained for the possibility of an isolated Ebola case here in the United States. But in the meantime we’ve got to make sure that we continue to provide the support of health workers who are going overseas to deal with the disease where it really has been raging."

Obama, who said he spoke on the phone Tuesday with recovered nurse Amber Joy Vinson, said the international community is making headway in fighting the disease.

"The point is this disease can be contained. It will be defeated," the president said, adding that the DART team is serving as "the strategic and operational backbone of America’s response" in Africa. "And the good news is that it’s starting to have an impact, based on the conversations that I had today with them, they’re starting to see some progress in Liberia, and the infrastructure is beginning to get built out.... And it’s critical that we maintain that leadership."

On the home front, Obama made a point of saying that with Vinson's release, "Of the seven Americans treated for Ebola, all have survived," while Craig Spencer was still undergoing treatment at New York's Bellevue Hospital.

The president added that when it comes to these health workers' reentry to the U.S., "We can make sure that when they come back, they’re being monitored in a prudent fashion, but we want to make sure that we understand that they are doing God’s work over there, and they’re doing that to keep us safe."

Obama's comments came less than an hour after White House spokesman Josh Earnest said the administration was imposing different Ebola monitoring requirements on military personnel and civilian health-care workers returning from West Africa because " it’s simply easier" to monitor the thousands of troops coming back from the region by limiting their movements.

"When we’re talking about our civilian government, or our civilians, and what sort of policy is in place to monitor the health of health-care workers who are returning from West Africa, we’re talking about a couple of dozen health-care workers a week who are returning to this country from West Africa," Earnest told reporters. "When we’re talking about military personnel, we’re talking about thousands of military service members who have been or will be deployed to West Africa to carry out the mission that the president ordered.

"And it simply will be easier to directly and actively monitor their health if their movements are restricted to certain locations," he added. "We’re talking about thousands of military personnel that are traveling from bases all across the globe, and in order to monitor their health, it’s simply easier to do that if their movements are restricted and they’re all co-located."

Even as he defended the difference between the two policies -- both of which were announced Monday -- Earnest emphasized it made no sense to try to extend the Pentagon's approach to a civilian population.

"It would be wrong to suggest that it would make the American people safer to apply this military policy in a civilian context," he said. "The science would not back that up. In fact, implementing this military policy in a civilian context would only have the effect of hindering our Ebola response by dissuading civilian doctors and nurses from traveling to West Africa to stop the outbreak in its tracks."