Former Transportation Secretary Pete Buttigieg said on Friday that he and his husband had been separated from their 4-year-old twins after an anonymous report falsely accused Mr. Buttigieg of posing a threat to their children.

The separation lasted for 24 hours and required their children to sit for interviews with Children’s Protective Services, Mr. Buttigieg said.

The Michigan State Police and C.P.S. determined the report was false, a spokeswoman for the state police said in a statement, adding that “false reports are dangerous.”

“I’ve been through political attacks in office, death threats in public life, and rocket attacks in war,” Mr. Buttigieg, a military veteran, wrote in a Substack post titled “A Terrible Thing Happened to My Family.” “But this is the ugliest thing that has happened to me since my career in service began.”

Mr. Buttigieg noted that the incident occurred soon after the Buttigiegs shared images of their family for Father’s Day, and also during Pride Month.

Mr. Buttigieg, a Democrat, ran for president in 2020, was the first openly gay cabinet secretary and is widely seen as a 2028 presidential contender. He has long weathered attacks over his sexual orientation.