Although the nation is on tenterhooks following the terrorist attacks in Paris earlier this month, 150 passengers arriving at Kennedy Airport from Mexico on Friday were able to leave the airport without going through customs, the New York Daily News reports.

Sources tell The Daily News that passengers on American Airlines Flight 1671 arriving at JFK from Cancun, Mexico, last week simply walked out of the airport without ever having to present their passports or check in with Customs and Border Protection.

“Some passengers on Flight 1671 did not complete immigration and customs process upon arrival when they were inadvertently directed to the domestic terminal,” American Airlines said in a statement to The Daily News.

The airline reportedly told the passengers to return to the airport and check in with customs. As of Sunday 144 passengers had returned for processing and an official told The Daily News that the remaining passengers were U.S. citizens.

American Airlines is working with Customs and Border Protection to ensure they “complete the process and to prevent this from happening in the future,” the company also said in the statement. “None of us went through immigration or customs,” a passenger told The News, adding, “There were no signs for customs or anything. The only signs we saw were baggage claim and exit.” The passenger complained Saturday that agents have “been harassing me with phone calls — they’re coming from high-up people at American Airlines, (Transportation Security Administration) and customs . . . . They’re very aggressive.” Another passenger also said that agents had been reaching out constantly.

Customs and Border Protection told The Daily News that it is “aware of and looking into the incident and is working with our counterparts to resolve it.”