– St. Louis County officials said Wednesday an uptick in confirmed COVID-19 cases has been tied to St. Ann's Residence, an assisted-living facility in Duluth. On Thursday, state numbers included the county's first death from the coronavirus.

"These are the kind of situations we've been preparing for, but it is still concerning, and a grim reminder of the seriousness of COVID-19, and how quickly it can spread," Amy Westbrook, St. Louis County's public health director, said in a news release.

The number of confirmed cases jumped Wednesday from 17 to 28, the largest day-over-day increase the northeastern Minnesota county has seen. On Thursday the number rose to 33 cases, including its first death. At least two of the newly diagnosed — a man in his early 70s and a woman in her late 80s — are currently hospitalized, along with three others who were previously tested.

"We recognize that St. Louis County has seen a recent increase in cases, but we want people to know that those cases are really the tip of the iceberg," Kris Ehresmann, the Minnesota Department of Health's infectious disease director, said at a news conference Wednesday.

The county's news release said "a large percentage" of the cases are linked to St. Ann's, where a resident tested positive for COVID-19 last week. Nine of the new cases reported Wednesday were individuals in their 70s or older.

St. Ann's did not immediately respond to a request for comment.

St. Louis County leaders are also now warning that the new coronavirus is spreading through community transmission, meaning public health officials cannot identify where an infected person caught the contagion.

"We have seen several cases this week that do not appear to be linked to travel, nor are they linked to previously confirmed cases," Westbrook said.

Nursing homes and assisted-living facilities across the state have been on lockdown for weeks to protect the elderly population that is particularly vulnerable to the virus. As of Tuesday, there were 20 deaths from COVID-19 among residents of senior care facilities in Minnesota.

At least one case of COVID-19 has also been confirmed at Superior View Apartments, a long-term care facility in Duluth.

The state Health Department has said it is focusing testing of new COVID-19 cases on these sites and implementing aggressive measures to curb the spread of the virus.