The last of 111 bodies of persons killed in this city's worst disaster were pulled from the lobby of the Hyatt Regency Hotel early today after the collapse of two walkways above the hotel lobby transformed a festive dance contest into a scene of terror.

City officials and hotel owners said late today that the cause of the disaster remained unknown and promised a thorough investigation.

There were fears that the number of dead could rise. Officials said almost 200 persons were injured, and six or seven were in "extremely critical" condition.

The last body was pulled from the rubble at about 9 a.m. today by some of the more than 500 rescue workers who had worked through the night.

At one point, rescue workers pulled back a huge chunk of steel and concrete debris and found 23 bodies crushed beneath it.

"Everyody in this city is heartsick," Mayor Richard L. Berkley said at a news conference this afternoon.

He said it was "premature to try to assume any fault" but added that "obviously, there is fault."

The accident occurred Friday night in the hotel's four-story lobby building, adjacent to the main 40-story hotel tower. The lobby building is connected to the main tower by three walkways, known as "skywalks" and estimated to weigh 32 tons each.

The collapse dumped tons of steel, concrete and glass on dozens of couples, many of them elderly, who were enjoying an early evening "tea dance," a regular function at the one-year-old hotel. Officials estimated there were 1,500 people at the dance and elsewhere in the lobby building when the walkways collapsed.

Witnesses described the scene just before the accident occurred:

The Steve Miller Orchestra was playing the Duke Ellington compositon "Satin Doll" for the dance contest. High above the dance floor, on the fourth floor walkway, about 50 people peered down at the dancing couples.

Directly below the fourth floor walkway, 100 people watched the scene from the second-floor walkway.

Then just after 7 p.m., officials said, the fourth-floor walkway suddenly buckled in the center, crashing down onto the second floor walkway and smashing it onto the dance floor. A walkway at the third-floor level is off to the side and remained in place, although it cracked when the others collapsed.

"We were sitting right there, watching the dancing," said Donna Bohner, 36, of Trenton, Mo., who was sitting on a stairway near the lobby when the accident happened. "We had just made the comment, 'Isn't this a nice place to spend the evening?' I'd say 60 to 70 percent of those people [on the dance floor] were white-haired people."

Fire captain Joseph Galeti said the first walkway to collapse appeared to have pulled loose from the steel rods that connected it to the ceiling. The rods were the only supports for the walkway, which consisted of a steel I-beam covered with metal sheeting and three inches of concrete.

"It looked like it pulled right off the rods. The nuts were still on the rods," Galeti told Knight-Riddler.

The fourth floor walkway cracked in two places near its center. As it plunged roughly 60 feet toward the floor, taking the second floor walkway with it, the falling debris severed a number of water pipes which began to gush water onto the chaotic scene on the lobby floor.

Michael Lonshar, 27, a salesman from Kansas City, was in the lobby at the time.

"There was a crack, like a firecracker," he said in describing the sound as the first walkway began its plunge.

"The place was packed," Lonshar said. "Suddenly there were people and water flying everywhere."

Lonshar said the top walkway plunged straight down.

"It hit the second one and there must have been 75 or 100 people on that," he said. "And then that fell and there must have been 100 to 150 people below that. It all looked like a human sandwich -- arms and legs hanging out."

The second-floor walkway was supported by steel rods that extended into the bottom of the fourth-level walkway directly above it. Officials said it was not clear whether the higher walkway began to buckle on its own or whether the weight of the crowd on the lower walkway pulled the higher structure down.

What followed the collapse of the walkways was hours of terror for the victims and frantic work by rescue teams seeking to free them.

"I personally saw one woman having a heart attack," said Ron Norman, disaster specialist for the Greater Kansas City Area Hospital Association.

"One guy was pinned between two beams that fell," Norman continued. "One beam ran from his crotch across his shoulder. He was in severe shock and his leg was crushed under the beam. In order to get him out, they used a chain saw to cut his leg."

Three construction cranes were rushed to the hotel to help clear the debris. As rescue crews worked, cries for help could be heard from victims trapped beneath the rubble. Rescue workers used small tubes to pump oxygen to some of those trapped.

Throughout the night, ambulances lined up outside the hotel to take the injured to the 14 hospitals that were used in response to the emergency. Officials estimated that half the ambulances in the Kansas City area were called to the scene.

By late this afternoon, what had been a scene of chaos hours earlier was eerily quiet. A small crowd of onlookers stood in a light rain across the street from the hotel, watching workmen boarding up the smashed glass in the front of the lobby building. Most of the hotel guests had claimed their luggage from the hotel garage where it was stored overnight and had scattered to other hotels.

City officials said the Hyatt Regency will remain closed indefinitely and will not be allowed to reopen without obtaining new city permits. The officials said no permits would be granted until after an investigation into the design and construction of the hotel, one of the largest in Kansas City.

The hotel opened on July 1, 1980. It is located on 3.2 acres in a fashionable commercial district just south of downtown Kansas City.

The hotel is managed by the Hyatt Hotel organization but is owned by the Crown Center Redevelopment Corp., which is a wholly owned subsidiary of Hallmark Cards Inc.

This afternoon Donald J. Hall, president of Hallmark Cards, issued a statement saying that "the past 18 hours have been the darkest of my life as well as one of the worst nights in the history of Kansas City."

Hall promised that his firm would hire "independent experts" to conduct "an extensive investigation into the causes of the accident."

At a news conference here this morning, Pat Foley, the president of the Hyatt Hotel chain, said Hyatt's investigation would center on a possible structural failure in the walkways.

"The architects, building contractors and his subcontractors had assured us of the structural integrity of the building," Foley said. "We're getting all the facts as fast as we can. The catwalks were designed to hold people shoulder to shoulder, as many as you can jam in there."

Like the hotel owners and managers, city officials said they had no idea what had caused the collapse. They said the hotel was built to meet local building standards, which they said are the same as the standard national building codes.

Mayor Berkley said he had already ordered city officials to begin gathering all of the documents that deal with construction of the hotel for the investigation, which could take weeks or months.

Among those who attended the news conference was Sen. John Danforth (R-Mo.), who is up for reelection next year. Danforth flew to Kansas City from Washington today, and later went to a local blood bank to donate blood for the victims. At the news conference, he sported a tag that said, "Blood Donors are Better Lovers."

The collapse of the walkways inside the Hyatt was the second major hotel disaster to occur in the past year. In November 1980, a fire swept the MGM Grand hotel in Las Vegas, leaving 84 people dead.