( CNN ) -- Two people are missing and at least 14 people were injured when a gas line in Kansas City , Missouri , exploded and ignited a four-alarm fire , officials said Tuesday night . The explosion apparently leveled JJ 's restaurant , a popular spot in Country Club Plaza , an upscale shopping district and residential neighborhood that is a regional gathering place . James Garrett , a spokesman for the Kansas City Fire Department , said three people were unaccounted for Tuesday night . Missouri Gas Energy said : `` Early indications are that a contractor doing underground work struck a natural gas line , but the investigation continues . '' Mayor Sly James said the walls of the restaurant had collapsed . Dr. Leonardo Lozada , the chief physician at St Luke 's Health Systems , said he heard the explosion at the hospital , which is a block and a half from the restaurant . `` Yes , it was pretty loud . I just heard it ; it was n't that traumatic , '' he said , adding that some people told him they saw the roof blow off . Officials at three hospitals indicated at least 14 people were hospitalized , including three in critical condition and three in serious condition . The number of injured had dropped from previous reports because there was `` a lot of confusion with people coming into the emergency room . '' Lozada told CNN . Two patients are in critical condition at St. Luke 's Hospital , said Dr. Marc Larsen . One of the patients suffered extensive burns ; the other facial trauma , he said . Most of the five other patients suffered minor lacerations or inhalation injuries , he said . Lozardo said one man had burns to `` 40 % percent of his body , mostly to his lower extremities . '' Garrett said here were no fatalities at the scene , but two of those hurt had life-threatening injuries . About 100 fire fighters fought the fire before it was put out , fire chief Paul Berardi said . When the first fire trucks arrived the restaurant was fully involved with a few people inside , he said . Witness says man told her to leave restaurant . One witness told CNN affiliate KSHB a man who had a hand-held device came into the restaurant before the blast and told her and 10 others in JJ 's to leave . Jennifer Carter told the station that restaurant workers already had turned off the appliances because people inside had smelled gas . She said she left when told and was a few blocks away when she heard the explosion . Garrett confirmed that workers from Missouri Gas Energy were `` on the scene '' before the explosion . Residents who live near JJ 's said they reported smelling gas to the utility company about an hour before the explosion , according to CNN affiliate KCTV . The explosion shook doors and windows at nearby businesses and homes , the station reported . James , who came to the scene from his office , said his primary focus was the victims . `` That 's the main concern , making sure they come out OK , '' he said . Garrett said gas lines have been shut off . `` People are still not allowed back into the plaza , '' he said . `` I do n't know when it will reopen -- hopefully tonight . '' CNN 's Carma Hassan and Cristy Lenz contributed to this report .
NEW : Utility company said it appears contractor struck a gas line . Two people also missing , Kansas City fire department says . Witnesses say roof blew off restaurant . Score: 6