Authorities had no reason to believe anyone was left in the buildings after crews searched the area, Percival said late Thursday. Buildings for several blocks in all directions remained evacuated.
A total of seven people, including the woman who died, were transported to the hospital. An eighth person went unassisted later, Percival said. He didn't know the conditions of the patients.
Authorities did not know whether the restaurant was open when the explosion occurred around 2:30 p.m. or how many people were inside.
The person who died was one of two women rescued from a shop next to the Branch Inn restaurant, Fire Chief Chris Riley said. At least five of the injured people were in the restaurant, Percival said.
Firefighters dug a man out of the rubble of the restaurant around 6:30 p.m. Riley said he was conscious and talking. Smoke still rose from the rubble hours after the explosion. Glass block, bricks and other debris were strewn more than 100 feet from the restaurant. The third-floor windows of an apartment across the street were blown out.
The Branch Inn sign lay on its side in the street, and an odor of burnt plastic filled the air. The blast blew the restaurant's front door into an intersection, where a hinge lodged in the fender of a sport utility vehicle waiting at a stop sign.
The SUV driver, 35-year-old Christine Guerin, said she was looking for a business when she heard an explosion and saw glass flying toward her.
"You couldn't even see the building. It was just smoke, black smoke," she said, noting she could hear a hissing noise and smelled gas after she got out of her car.
Police quickly arrived quickly and began escorting people away. Percival did not know what type of business was in the adjacent building. He said the neighborhood is dotted with boutiques that sell clocks, antiques, clothing and gifts.
"I don't recognize what's there," he said.
Pueblo, a city of about 106,000, is 100 miles south of Denver.