An "accidental natural gas explosion" at a South Side motel left two people severely injured and displaced 18 others early Friday morning, San Antonio Fire Department arson investigators said.

The explosion was reported just before 4:30 a.m. at the Ever-Kleen Motel located in the 1300 block of Roosevelt Avenue, not far from East Mitchell Street and Mission Concepción on the city's South Side.

San Antonio Fire Department Chief Charles Hood said the fire was caused by an explosion in one of the rooms which also damaged four others.

People staying at the motel described the noise as a shotgun-like sound, except much louder.

"I looked up and was like, 'Oh my God, there's a fire,' and then saw my friend on fire. She was literally burned and our other friend he was screaming he was burnt too, and everybody was just freaking out," said Monica Gomez.

RELATED:Man found burning in home may have accidentally set himself on fire, SAFD says

RELATED: Mobile home destroyed by overnight fire in South Bexar County

Hood said a man in his mid-30s and woman in her mid-20s were taken to San Antonio Military Medical Center for treatment. He said they both have first-degree burns, and that one of the victims had burns on over 70 percent of their body.

Eighteen people have been displaced by the fire. An additional person was also treated for smoke inhalation at the scene.

No firefighters were hurt while putting out the fire.

Outbrain