KANSAS CITY, Missouri - A fire triggered by a natural gas explosion that appeared to have originated underground engulfed a restaurant in Kansas City, Missouri, on Tuesday, injuring at least a half dozen people, authorities said.The gas explosion shook the Country Club Plaza, an upscale shopping area about 30 blocks south of downtown Kansas City, just after 6 p.m. local time, Kansas City Fire Department spokesman James Garrett told CNN.Garrett said 14 people were injured. Nine were taken to hospitals, including two with life-threatening injuries.