A man has been arrested after landing a gyrocopter on the west lawn of the US Capitol in Washington DC.
Capitol Police said nearby streets have been closed and the Capitol Visitor Center placed on temporary lockdown as the aircraft is investigated.
The man's identity and motive were not immediately clear.
But the Tampa Bay Times reports the pilot is a Florida man who wanted to stage a protest calling for campaign finance reform.
The demonstrator, postman Doug Hughes, reportedly had leaflets for US lawmakers declaring a "voter's rebellion".
The letters said: "As a member of Congress, you have three options. 1. You may pretend corruption does not exist. 2. You may pretend to oppose corruption while you sabotage reform. 3. You may actively participate in real reform."
Mr Hughes told the Tampa Bay Times the US Secret Service had questioned him about his plans last year.