The screenings aren’t going to start for a few days, one source with knowledge of the plans said, CNN reported.

The source said the screenings will target those passengers whose flight itineraries originated in the West African countries where Ebola’s already been found, CNN reported.

The details of the screening plan haven’t yet been released.

The move comes amid growing concerns about the spread of Ebola in the United States. The Association of Flight Attendants has called on government health officials to implement better screening procedures for passengers coming from known Ebola areas, Forbes reported.

The AFA is the largest flight attendant union in the United States, representing 60,000 workers on 19 airlines.

“If an infected passenger enters the U.S. on a commercial flight, it will be the Flight Attendants on that aircraft who are oct likely to be exposed,” said Sara Nelson, AFA International president, in Forbes. “Once an infected person is in flight, the options are limited.”