KHSB-TV via Reuters Firefighters working at the scene of a fire triggered by a natural gas explosion in Kansas City on Tuesday night.

At least 14 people were injured and two others were missing after a fire triggered by a natural gas explosion Tuesday in an upscale business and shopping district of Kansas City, Mo., authorities said.

Kansas City police said the blast occurred about 6 p.m. (7 p.m. ET) outside JJ's Restaurant in Country Club Plaza. Enormous flames tore into the night sky outside the restaurant, which was at the center of the fire and was destroyed, NBC station KSHB reported.

Kansas City Fire Chief Paul Berardi told a news conference that the cause of the explosion was under investigation but said foul play was not suspected.

Early Wednesday, KSHB quoted Berardi as saying that a man and a woman were missing.

"We are concerned that there may be additional people that were not able to get out of the structure," Berardi told reporters. "I always fear there may be fatalities in a situation like this."

A statement released by the Missouri Gas Energy company said early indications are that a contractor doing underground work struck a natural gas line, but the investigation continues.

At the news conference, Berardi said MGE had turned off the gas at 8 p.m. local time (9 p.m. ET) and there was no danger of another explosion occurring in the area. The chief acknowledged the department had received earlier reports of gas odor in the area.

Authorities had told NBC News earlier in the evening that the explosion occurred when a car struck a gas main.

"Get out! You are not safe right here! Please!" rescue crews could be heard urging people who were trying to get a look at the scene in the blast's aftermath.

"Fire is mostly under control," Kansas City Mayor Sly James said on Twitter at about 8 p.m. ET, but numerous crews remained on the scene nearly an hour later as flames spewing thick, black smoke continued to burn.

Kansas City, Missouri, Fire Chief Paul Berardi and Mayor Sly James hold a news conference to update the media on the explosion and fire that burned down a landmark restaurant. Video courtesy KSHB-TV.

According to The Associated Press, City Manager Troy Schulte said he had not heard of any fatalities and was not aware of anyone being reported missing. After 10:30 p.m. ET, authorities began searching the scene with cadaver dogs.

At least 11 ambulances responded, fire officials said. A physician at Saint Luke's Hospital said in a brief news conference the hospital had received five patients, including two patients in critical condition -- one with severe burns and another with deep lacerations.

University of Kansas Hospital had received six injured people, including two in serious condition and one critical. Two patients drove themselves in with minor injuries.

Two patients arrived at the Research Medical Center, and another at the Truman Medical Center.

Witnesses told KSHB that they smelled natural gas in the area of the restaurant at least an hour before the explosion.

The blast occurred during the dinner hour at JJ's Restaurant, a Kansas City institution dating to 1985. JJ's is widely regarded as one of the best dinner spots in the Midwest, earning a 93 rating from Zagat's, and its wine cellar has been listed by The Wine Spectator as one of the finest in the world.

Carlo Dellaverson, Sossy Dombourian, Gina Gentilesco and Zoya Khan of NBC News contributed to this report.

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