All Minneapolis fire stations were on lockdown for more than three hours Monday night after information surfaced about the potential for civil unrest, according to a statement released Tuesday by the Fire Department.

The statement did not specify who might carry out the anticipated unrest and for what cause.

The city has experienced several rounds of protests and at least two outbreaks of destructive rioting since the May 25 death of George Floyd while being detained by Minneapolis police.

Some of the strife included damage to two police precinct headquarters in south Minneapolis.

The lockdown covering all 19 stations lasted from 6:40 to 10 p.m. and kept all crews indoors unless they were responding to an emergency, the department's statement said.

The department went on to explain the lockdown was needed "as a precautionary measure based on intelligence the department received regarding the possibility of civil unrest."

Assistant Fire Chief Bryan Tyner would say only that "law enforcement surveillance" was the source of the information leading to the lockdown.