MINNEAPOLIS — Minnesota Gov. Tim Walz put himself into quarantine Monday after a member of his security detail tested positive for COVID-19, while U.S. Sen. Amy Klobuchar said her husband has been hospitalized with COVID-19.

The announcements followed an Instagram post by Lt. Gov. Peggy Flanagan late Sunday that her brother died of the disease in Tennessee.

Minnesota’s number of confirmed cases shot up to 235 as of Monday, a jump of 66 new infections. One person has died and no new deaths were reported. Health officials said the number of Minnesotans with the virus is likely much higher.

The rapid developments came as the 55-year-old governor considers whether to order Minnesota residents to shelter in place. Walz spokesman Teddy Tschann said Walz did not plan to issue a shelter order Monday, but that discussions were ongoing within the administration.

The governor will self-quarantine for 14 days. Walz learned of the potential exposure early Monday morning and has not left his home since, his office said in a statement. He was in proximity to the individual late last week.

“The most important thing Minnesotans can do to stop the spread of COVID-19 is to stay home,” Walz said. “I’m using this as an opportunity to lead by example. Though I’m feeling healthy and not showing any symptoms, I’m going to work from home and model the protocol we are asking all Minnesotans to follow.”

Klobuchar said in a statement that her husband, John Bessler, began feeling sick when she was in Minnesota and he was in Washington, and that he immediately quarantined himself. The former presidential candidate said her husband sought a test and chest X-ray after he began coughing up blood, and that he was checked into a Virginia hospital with “very low oxygen levels, which really haven’t improved.”

Bessler developed pneumonia and was on oxygen but not on a ventilator, Klobuchar said.

“He is exhausted and sick but a very strong and resilient person,” she said.

Klobuchar said her doctor had advised her not to get a test because they had been in different places for the last two weeks and she was outside the 14-day period for getting sick, so she didn’t qualify for testing.

Flanagan said her brother, Ron Golden, died on Saturday in Tennessee. He had been diagnosed with cancer several weeks ago and his immune system was compromised, she said. He was put in a medically induced coma and placed on a ventilator.

“He fought it as hard as he could but it was simply too much for his body. THIS is why we must #StayHome,” she wrote. “If you feel fine, that’s great. But please consider the possibility that you’re carrying the virus and don’t know it, and then you walk past the next Ron, my big brother, in public.”

Flanagan wrote that her brother was Tennessee’s second COVID 19-related death.

For most people, the coronavirus causes only mild or moderate symptoms, such as fever and cough. For some, especially older adults and people with existing health problems, it can cause more severe illness, including pneumonia. The vast majority of people recover within weeks.