The White House press room was shortly evacuated as reporters had gathered for a scheduled briefing.
While White House spokesman Josh Earnest was speaking, the Secret Service interrupted the Tuesday briefing.
Later, the evacuation turned out to be in response to a bomb threat.
The threat had specifically been made against the briefing room, Earnest said, adding, the agents "determined that for the safety of all of us they needed to evacuate all of us and sweep it,"
The evacuation, which took about 30 minutes, came hours after another one at the Dirksen Senate Office Building by Capitol Police.
"All press come with me please," an officer shouted as Earnest was speaking about cybersecurity.
The Secret Service agents inspected the room with bomb-sniffing dogs and minutes later the reporters were told to return.
A major security lapse occurred in September when a US war veteran was able to enter the main floor of the White House with a knife, an unprecedented security breach in recent decades.
NT/NT