Ahead of potential civil unrest due to Tuesday’s presidential election, the National Guard is on standby as a precaution in several states, including Washington state and Oregon, where hundreds of ballots were damaged or destroyed after at least three ballot drop boxes were recently set on fire, officials say, Report informs via CNN.

Almost all the ballots set ablaze on Monday were in a drop box in Vancouver, Washington, while most ballots in a drop box in Portland, Oregon, survived a fire set the same day, election officials said. The incidents are believed to be connected to a third fire on October 8, also in Vancouver. Portland police released a physical description of a suspect but said they’ve not identified him.