(KANSAS CITY, Mo.) -- A body was recovered Wednesday morning from the scene of a natural-gas explosion that ripped through a popular downtown restaurant in an upscale section of Kansas City, Mo., Tuesday night, leaving 15 people injured.

The body has yet to be identified.

Witnesses say the huge fireball, which engulfed an entire city block Tuesday night, could be seen for miles. The explosion destroyed JJ's restaurant and rattled windows blocks away.

St. Luke's Hospital said it treated eight patients, including two men who were in critical condition. Six other people had less serious injuries, according to ABC affiliate KMBC-TV. The University of Kansas Hospital said it had received four patients and had a fifth on the way, KMBC reported.

More than 100 firefighters worked overnight to knock back the thick black smoke and shooting flames that forced onlookers to flee the downtown Kansas City shopping district just after 6 p.m.

Investigators are sifting through the rubble and trying to figure out what caused the blaze. It is believed that a contractor might have hit an underground natural-gas line.

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