A stray bullet hit a young woman riding a Metrocable, a cable-car system in the northwestern Colombian city of Medellin, television stations reported.
The woman was taken to a clinic after being hit in the leg on Saturday and is in a stable condition.
Residents said this was not the first time that a bullet had pierced a cable-car cabin in the area.
"This was a case of shots being fired into the air by residents who were partying in the sector," the police commander in charge of security for Metrocable, Col. Edgar Moreno, told the El Tiempo newspaper.
Moreno said the incident was not an attack on Metrocable, which is used by some 300,000 people in the northeastern section of Medellin, the capital of Antioquia province.
The cable-car system is one of Medellin's best-known tourist attractions, having carried Spain's King Juan Carlos and Queen Sofia.
Metrocable connects to the Medellin Metro, providing transportation for thousands of people who live in the crime-ridden city's poor neighbourhoods.