US police are investigating tweets by a satirical news website about a fake security alert at Washington DC’s Capitol building.
The Onion said on its Twitter account that "screams and gunfire" had been heard inside the Capitol. It later said schoolchildren had been taken hostage.
Capitol Police said there was "no credibility to these stories", and that the security situation was "normal".
The Onion told the BBC that its Twitter account had not been hacked.