Colombian authorities are investigating after bullet holes were discovered on an American Airlines flight that traveled between Medellin, Colombia, and Miami, ABC News reports.

No injuries were reported and officials say the preliminary investigation indicates the flight was struck while landing in Medellin on Sunday, according to Colombian officials.

American Airlines said its teams "identified a puncture" to the plane’s exterior during a routine inspection when it returned to Miami.

“The aircraft was immediately removed from service for further inspection and repair. We will work closely with all relevant authorities to investigate this incident,” the airline said in a statement to ABC News.

Authorities say they are focusing on a criminal group behind this incident, but nothing is conclusive.  

Flightradar24 data shows the Boeing 737 MAX 8 traveled from Medellin to Miami on Monday morning and then from Miami to Dallas later that evening.

Dallas-Fort Worth is the headquarters for American Airlines and the plane was sent there for complete repairs, according to the airline.

American Airlines said the puncture did not cause any issues with flying the plane.