White House briefly locked down amid security alert
The White House was briefly locked down as US Secret Service agents cleared the area around the presidential compound.
It is not immediately clear what caused the security situation.
Secret Service stepped up security around 4pm on Tuesday, with dog units and other agents seen gathering on the North Lawn.
Reporters working inside the White House were kept inside by automatically locking doors.
The lockdown was lifted shortly after, and visitors and staffers could be seen walking about the complex.
The Secret Service did not immediately respond to inquiries about the situation. In the past, fence-jumpers at the White House have triggered similar security responses.
President Barack Obama is at the White House after returning from an international trip to the Middle East and Europe.