Spicer tweeted that the incident occurred on Pennsylvania Avenue.
President Donald Trump was not in town, as he is spending the weekend at his private Mar-a-Lago estate in Florida.
A similar incident occurred last week when an intruder was arrested after scaling three fences surrounding the White House perimeter. Authorities said the man was on the grounds for 17 minutes and able to “rattle the door handle,” according to House Oversight and Government Reform Committee Chairman Jason Chaffetz. The President was in the White House during that incident.