The White House went under lockdown on Friday due to "suspicious activity", the US Secret Service said.
"North fence line of @WhiteHouse is closed due to suspicious activity, uniformed division is responding, " the Secret Service tweeted.
It later said the suspect has been caught.
Reporters at the White House said earlier that they were told to leave the north lawn due to an unknown reason.
The incident took place just after US President Donald Trump left for his trip to Hawaii and Asia.