Newark Liberty International Airport was under a ground delay ordered by the Federal Aviation Administration on Thursday afternoon due to issues with equipment.

"The FAA canceled the ground stop and is now slowing flights into Newark Liberty International Airport due to equipment issues that affected some radio frequencies in the Philadelphia TRACON area that handles Newark arrivals and departures," a spokesperson for the FAA said in a statement, according to CBS News. "We are investigating the cause."

Flights were delayed for roughly 90 minutes. 

Newark Liberty International Airport has had to limit flights due to equipment issues and problems with air traffic control staff in the past.

The FAA suggested that the slowdown could continue into October of this year.