"The first thing we need to be concerned about is the people that are injured," said Mayor Sly James, who also praised the work of first responders. James said officials were in contact with Missouri Gas Energy.
The University of Kansas Hospital was treating five people injured in the blast, said spokesman Bob Hallinan. He said one person was in critical condition, two were in serious condition and two others were expected to be released. He said all the injuries were traumatic, such as broken bones, rather than burns or smoke inhalation.
Kerry O'Connor, a spokeswoman for St. Luke's Hospital, which is near the scene of the fire, said several patients were on the way to the hospital. She said they haven't been assessed yet but "they appear to be critical at this time."
Fire officials didn't immediately return a phone call seeking comment Tuesday evening.
The smell of gas remained very strong near the area long after the suspected explosion.
There were signs that utility work was being done in area. A phone message left Tuesday seeking comment from Missouri Gas Energy was not immediately returned.
Jim Ligon, a bartender who has worked at JJ's restaurant for five years, wasn't working Tuesday night but said he started getting texts and calls from co-workers minutes after the explosion.
He said the incident happened during the peak of weekday happy hour, when there is typically anywhere from 15 to 45 people in the bar area as well as three to five tables of diners at the restaurant.