WASHINGTON (AP) — The Federal Aviation Administration announced Wednesday that it will reduce air traffic by 10% across 40 “high-volume” markets beginning Friday morning to maintain safety during the ongoing government shutdown.

The agency is confronting staffing shortages caused by air traffic controllers, who are working unpaid, with some calling out of work during the shutdown, resulting in delays across the country.

FAA Administrator Bryan Bedford said the agency is not going to wait for a problem to act, saying the shutdown is causing staffing pressures and “we can’t ignore it.”

Bedford and Transportation Secretary Sean Duffy said they will meet later Wednesday with airline leaders to figure out how to safely implement the reduction.