Updated

At least 11 people were killed at one Joplin nursing home by the tornado that devastated the southwest Missouri city, the home's operator told The Associated Press on Tuesday.

Bill Mitchell, who operates Greenbriar nursing home on the city's south side, said 10 residents and a staff member were among the nearly 120 people killed by Sunday evening's twister. One person remained unaccounted for Tuesday, he said.

The tornado tossed three vehicles into Greenbriar's building and left only one 10-foot section of an interior wall standing, Mitchell said.

"What used to be a building was nothing more than a pile of rubble," said Mitchell, the Senior Vice President for Health Facilities Management Corp., based in Sikeston, Mo.

Staff at Greenbriar and another heavily damaged facility, Meadows Care Center, had received a warning that the storm was coming and started moving people into the halls. But it hit quicker than expected, Mitchell said.

More warning, he said, "wouldn't have mattered."

Greenbriar, which had 89 residents at the time of the tornado, and Meadows Care Center, which had 104, have sent survivors to other facilities in Springdale, Ark.; Grove, Okla.; and Wichita, Kan., Mitchell said.