The officer told reporters that the White House was going on lockdown and to stay inside.
After an hour, the lockdown was lifted.
On March 19, a man approached the White House checkpoint and said he had a bomb inside his car.
Earlier in March, an intruder carrying a backpack breached the outer perimeter of the White House and was arrested by the US Secret Service near the south entrance to the residence.
It is not unheard of for intruders to scale the White House perimeter fence, and those that do are usually caught quickly and handed over to local police. The most serious recent security breach of the White House was in 2014, when an intruder with a knife jumped the fence, ran through the front door and made it all the way into the East Room, often used for receptions and addresses, before being tackled by security.