Jacques Brinon/AP

It's not a outright Ebola travel ban, but the federal government is limiting the ways in which passengers from West Africa can enter the United States.

The Department of Homeland Security on Tuesday announced that travelers from Liberia, Sierra Leone, and Guinea—the three countries at the center of the Ebola outbreak—will have to fly into the U.S. through one of five airports: New York's JFK, Washington D.C.'s Dulles, Atlanta, Chicago O'Hare, and Newark, N.J. Those are the same five airports where officials began secondary screenings of travelers from those countries earlier this month.

"We are continually evaluating whether additional restrictions or added screening and precautionary measures are necessary to protect the American people and will act accordingly," DHS Secretary Jeh Johnson said in a statement.

The new measures come amid mounting pressure from both Republicans and Democrats for the government to ban all inbound travel from those countries. Vulnerable Senate Democrats have joined those calls in recent days as the spread of Ebola has become a top issue in the midterm election campaigns. Senior medical officials and the White House have resisted such a move on the grounds that it would be harder to screen people who try to go around the ban and enter the U.S. discreetly.

There are currently no direct commercial flights from the three countries to the U.S., and Johnson said the five airports already accounted for 94 percent of the 100-150 people a day who fly into the country via connections in Europe.

"We are working closely with the airlines to implement these restrictions with minimal travel disruption," Johnson said. "If not already handled by the airlines, the few impacted travelers should contact the airlines for rebooking, as needed."

President Obama has not categorically ruled out a full travel ban, and already a few Republicans have predicted he may bend in the weeks before the November election.