An attempt to ran the White House gates ended with shots fired, U.S. senators put under lockdown in the Capitol, a female suspect dead, sources told ABC News.
A police officer was also reported shot, sources said.
Lawmakers reported hearing three pops that sounded like gunfire.
"We heard pops that sounded like shots," said Sen. Bob Casey, D-Pa.
"We heard shots. They told us to get behind a car," Sen. Sherrod Brown, D-Ohio, told ABC News.
"Close, lock and stay away from external doors and windows. Take annunciators, emergency supply kits and escape hoods; and move to your office's assigned shelter in place location or the innermost part of the office away from external doors or windows," Capitol Police told Congressional staffers staffers in an email.
The alert came around 2:25 p.m. when Capitol Police told the press and others in the Capitol to shelter in place and stay away from the windows.
Sources told ABC News that initial reports say someone tried to ram the gate at the White House, and then fled to Capitol Hill and shots were fired
The FBI is headed to Capitol Hill to assist in the investigation, officials told ABC News.
The Capitol this week is the center of a contentious political battle over an ongoing government shutdown.