U.S. police say the Capitol in Washington was locked down as a precaution after shots were fired nearby on April 11.
Spokeswoman Kimberly Schneider of the Capitol Police said in a statement that the suspected shooter has been "neutralized."
The statement did not give details of what happened to the suspected gunman.
It also said that police were investigating a suspicious package on the lower west terrace of the building.
Citing a federal official, NBC News reported that there are no indications the shooting was an act of terrorism.
Congress has been on spring break for two weeks and lawmakers are set to return to work on April 13.