Two Pokemon Go players went out of their way to help rescue two people trapped inside a burning warehouse over the weekend.

Matt Schwan and his friend Trey Plocher were playing the online game along the St. Louis riverfront late Saturday night when they smelled smoke and heard screams for help.

An overnight 4-alarm fire in an abandoned warehouse left one firefighter injured in the middle of a brisk winter storm overnight Saturday.

Just after midnight Sunday, the St. Louis Fire Department responded to a fire at the intersection of N. Lenor K. Sullivan and Biddle just north of the Arch.

Schwan called 911 and says the experience rattled his nerves.

"If no one else was down there they would've been toasted," said Schwan. "Knowing they're alive makes me feel a lot better. But still, that voice that I heard is the thing that's going to resonate with me for a while."

Upon arrival, firefighters rescued two people trapped inside of the engulfed warehouse. Firefighters believe the two people were trying to get out of the cold, and possibly had a makeshift stove.

Photos: 4-alarm warehouse fire challenges the cold

Visible fire and heavy smoke were seen throughout the entirety of the abandoned warehouse as firefighters fought to put out the flames.

St. Louis Fire Chief Dennis Jenkerson said the old building was once used as a cold storage facility. He says it's lined with cork that burns slowly and it could continue to smolder for quite a while.

The building smoldered for more than 24 hours before the fire was completely extinguished.

During the rescue, one responding firefighter was reportedly injured. They were later treated and released.