Hundreds of flights were delayed or canceled across the country on Friday after the Federal Aviation Administration announced that it would reduce air traffic by 10% at 40 major airports across the country amid staffing shortages triggered by the ongoing U.S. government shutdown.

According to the flight tracking website FlightAware, there were at least 800 flight cancellations and more than 1,000 delays as of 9 a.m. ET.

Transportation Secretary Sean Duffy said Wednesday that the reductions were an attempt to “alleviate the pressure” on air traffic controllers, who have been working without pay since the shutdown began. Absences at air traffic control towers have already resulted in flight disruptions.

“We’re not going to wait for a safety problem to truly manifest itself when the early indicators are telling us we can take action today to prevent things from deteriorating,” FAA Administrator Bryan Bedford said.

The list of affected airports includes some of the country's largest airports, such as New York’s John F. Kennedy and LaGuardia, Newark Liberty International in New Jersey, Los Angeles International, Atlanta’s Hartsfield-Jackson International, Boston’s Logan International and Chicago’s O’Hare.

Full list of affected airports

• Anchorage International (ANC)

• Baltimore/Washington International (BWI)

• Boston-Logan International (BOS)

• Charlotte Douglas International (CLT)

• Chicago Midway International (MDW)

• Chicago O'Hare International (ORD)

• Cincinnati/Northern Kentucky International (CVG)

• Dallas-Fort Worth International (DFW)

• Dallas Love Field (DAL)

• Denver International (DEN)

• Detroit Metropolitan Wayne County  (DTW)

• Fort Lauderdale-Hollywood International (FLL)

• George Bush Houston Intercontinental (IAH)

• Hartsfield-Jackson Atlanta International (ATL)

• Honolulu International (HNL)

• Houston Hobby (HOU)

• Indianapolis International (IND)

• Las Vegas Harry Reid International (LAS)

• Los Angeles International (LAX)

• Louisville Muhammad Ali International (SDF)

• Memphis International (MEM)

• Miami International (MIA)

• Minneapolis-Saint Paul International (MSP)

• New York LaGuardia (LGA)

• New York John F. Kennedy International (JFK)

• Newark Liberty International (EWR)

• Oakland San Francisco Bay International (OAK)

• Ontario International (ONT)

• Orlando International (MCO)

• Philadelphia International (PHL)

• Phoenix Sky Harbor International (PHX)

• Portland International (PDX)

• Ronald Reagan Washington National (DCA)

• San Diego International (SAN)

• Salt Lake City International (SLC)

• San Francisco International (SFO)

• Seattle-Tacoma International (SEA)

• Tampa International (TPA)

• Teterboro (TEB)

• Washington Dulles International (IAD)