Several passengers on a commercial flight from Cancun walked out of JFK airport without first passing through customs on Friday night.

American Airlines Flight 1671 landed at JFK at 8:50 p.m. on Friday, and "some" of the total 74 passengers left the airport without first passing through Customs and Border Protection for passport and bag checks, according to a spokeswoman for American Airlines.

Spokeswoman Martha Thomas said that JFK implements "dual use" gates for domestic and international flights—depending on the origin of the flight, one of two doors is opened at the base of the passenger walkway. Thomas said that the incorrect door was opened, and that airline employees realized the error before all passengers had been "inadvertently directed" into the domestic terminal.

Thomas also stressed that post-flight customs is the last step in the airline's security process, stating, "We... work closely with U.S. Customs and Border Protection (CBP) and the Transportation Security Administration (TSA) who vet all passengers prior to boarding any aircraft with a destination in the United States."

The airline reportedly spent the weekend summoning passengers back to the airport for customs processing.

"They said, 'If you don't come in Monday, we're sending FBI agents to your house,'" one passenger told the Daily News. (The tabloid also originally reported that 150 passengers exited the airport without passing through customs, a figure that American Airlines disputes.)

As of this morning, American Airlines says that all but one of the passengers, an American Citizen, have returned to the airport for customs processing.

US Customs did not immediately respond to a request for comment, but issued a statement to the News that it is "aware of and looking into the incident and is working with our counterparts to resolve it." TSA also did not respond to a request for comment.

American Airlines said, "We are reviewing the matter with CBP to ensure one U.S. citizen completes the process and to prevent this from happening in the future."