NEW YORK (PIX11) — Flights could be delayed by two hours at John F. Kennedy International, Newark Liberty International and LaGuardia airports Monday because of staffing issues, according to the Federal Aviation Administration.

The staff availability problems were “unexpected,” according to the FAA.

“The FAA must reduce the flow of aircraft around New York City to maintain safety,” the agency tweeted.

The FAA advised checking their site for updates on the situation at JFK, Newark and LaGuardia. The agency has not said what caused the staffing issue.