Washington:
The US Capitol was placed on security lockdown on Thursday after what senators and journalists said were shots fired outside Washington's seat of Congress.
"We heard what was about four shots," said Senator Bernie Sanders as tourists and lawmakers rushed into the building to take cover and police hurried to secure the area.
Emergency vehicles converged on the scene, focused on the north side of the iconic landmark, where an AFP photographer saw visitors scattering and ducking for cover.
Just over a mile away, the White House was also placed in lockdown, with Secret Service agents in tactical gear deploying around the building.
Senator Sherrod Brown told AFP he had been walking with a colleague from a nearby senatorial annex when he had heard shots and been forced to take cover behind an SUV.