Gunshots were fired at Kamala Harris' Arizona campaign office after midnight Monday.
No one was injured in the incident, which left bullet holes in the facade of the Democratic National Committee campaign office. Police have made no arrests, and they have not identified a motive.
Staffers found bullet holes in the windows Monday morning.
"No one was inside the office during the overnight hours, but this raises concerns about the safety of those who work in that building, as well as those nearby," Tempe Police spokesperson Sgt. Ryan Cook said.
Police said the shooting near is "being investigated as a property crime as no one was in the office at the time of the occurrence."
"We are grateful to Tempe Police for coming quickly to the scene and are fortunate no one was present or injured," Sean McEnerney, Arizona Coordinated Campaign Manager, said.
This is the second time the office has been damaged in recent days. BB pellets were fired at the office after midnight on September 16.
While it's unclear if the shooting in Arizona was political, there has been an uptick in violent threats on the campaign trail. President Trump has been targeted in two assassination attempts in recent months, one of which left him bloodied.
The suspect in the most recent attempt, Ryan Routh, was charged with attempted assassination Tuesday. The Justice Department has been accused of endangering Trump by releasing a letter Routh wrote offering a bounty to kill Trump.
A Virginia man was arrested in August for threatening to kill Harris in posts on social media.
Harris is planning to visit Arizona on Friday to see the southern border, with immigration rating as a top issue for voters in the presidential election. Arizona is one of the fiercely contested battleground states that will decide the outcome of the race.
Trump has blasted Harris as a soft-on-crime liberal who wants open borders and gun confiscation - an image Harris has tried to undercut by claiming to own a gun. Harris even joked to Oprah in a recent interview that anyone caught breaking into Harris' house "is getting shot."
"I probably shouldn't have said that, but my staff will deal with that later," she joked.
The Harris campaign has not specified what type of gun Harris owns.
