Barbed wire, is seen atop security fencing, with the dome of the U.S. Capitol Building on Saturday, Jan. 16, 2021 in Washington, DC. Kent Nishimura / Los Angeles Times via Getty Images The US Capitol went into lockdown Monday following an "external security threat," a message sent to people inside the complex read. Staffers in the building were sent an emergency message telling them "no entry or exit" into the building was permitted. Some people inside a portion of the Capitol building reported on social media that they had been evacuated. The alert was promoted following a fire at a nearby homeless encampment, law enforcement officials said. The fire was quickly extinguished, according to DC Fire and EMS, and the Capitol was taken out of lockdown just before 11:30 a.m. Visit Business Insider's homepage for more stories. The US Capitol was briefly placed into a lockdown Monday morning following an "external security threat" that turned out to be a fire at a nearby homeless encampment, law enforcement officials said.The lockdown was lifted just before 11:30 a.m.