A 15-year-old boy is being credited with saving over 100 people he led away from the terrorist massacre at a Moscow concert hall on Friday.

The teen, Islam Khalilov, works as a cloakroom attendant at the Crocus City Hall, where the shooting took place. His familiarity with the building allowed him to act quickly to guide terrified concertgoers to safety, preventing further deaths in Friday's massacre.

"At first we heard some strange sounds on the first floor. We thought maybe some noisy group had come," he explained later in an interview, according to the Daily Mail.

"I understood that if I didn't react, I would lose my life and the lives of many people," he added "Honestly, it was very scary."