"A man was arrested who entered a closed area by jumping over the perimeter fences," the police said in a message on Twitter.
It is noted that the incident took place on the evening of April 25.
The perpetrator was a 22-year-old Virginia resident.
The motives for his action are not reported.
The police preliminary concluded that this was an isolated incident.
On April 2, American police reported that an unidentified vehicle had run over a checkpoint near the Capitol.
One policeman was killed, one was injured.
The suspect passed away.