Update 3.49pm: The brief state of lockdown at the US Capitol has ended.
The incident, triggered by reports that a woman with a gun was attempting to enter the building in Washington DC, turned out to be a false alarm.
The all-clear was given within an hour, and normal operations quickly resumed at the Capitol, with visitors let inside and the House preparing to go back into session and vote.
Capitol Police officers and Sergeant at Arms officials had said they were searching for a woman in an office building tunnel leading to the Capitol.
One officer said she had something that looked like a gun in her bag.
The Sergeant at Arms later informed House leadership staff that it had been a false alarm.
The US Capitol building is on lockdown with police barring people from entering amid reports of a woman with a gun.
The Senate sergeant at arms issued a lockdown alert for the building and visitor centre, saying police activity had been reported.
Capitol office buildings are open.
Capitol police said they are searching for an individual but offered no details.
One officer outside the Capitol said police are responding to sketchy reports of woman who may have a gun.
House press gallery staff said the building is on lockdown but that the House met briefly and immediately recessed.
Scheduled voting was postponed.