The White House has returned to "normal operations" after a partial lockdown triggered when an individual threw a metal object over the fence, a U.S. Secret Service spokesman said on Monday.
"An individual threw a metal object over the north fence line at the White House. Secret Service Uniformed Division officers immediately apprehended the individual without incident. All protective sweeps of the metal object were met with negative results," spokesman Shawn Holtzclaw said in an emailed statement.
The north side of the White House was placed on a security lockdown on Monday because of a suspicious package, a Secret Service official said.
The partial lockdown on the Memorial Day holiday occurred while President Barack Obama was home.
Reporters were not allowed to leave the White House compound through its northwest gate and flashing lights from emergency responders could be seen nearby.
The official said hazardous material checks were being made.
Local news radio station WTOP reported that one person was in custody, citing a federal law enforcement official.
Obama had visited Arlington Cemetery earlier in the day as part of the annual commemoration for armed services members.