The US Capitol was put on lockdown and blocked for entry and exit over an "external security threat". Capitol Police have issued a warning to House and Senate offices asking people to stay away from exterior windows and doors and seek cover should the notice have been issued while they were outside a building.
The lockdown was triggered "out of an abundance of caution" over a fire that started at a nearby homeless encampment. The fire was soon extinguished and the lockdown lifted, with law enforcement saying that the threat has been eliminated.
Several videos and photos have emerged on social media showing smoke rising from behind the US Capitol building. Capitol Police have issued a statement saying that there are no fires "within the Capitol campus".
The inauguration rehearsal, which was taking place at Capitol Hill at the time, has been cancelled, with participants evacuated by security officials. It is unclear so far whether the rehearsal will continue now that the lockdown has been lifted.
The Capitol Hill security has been on high alert since some pro-Trump protesters attending the president's "Stop the Steal" rally stormed the Congress building on 6 January in bid to thwart the ongoing certification of the election results. The National Guard has been deployed to help the Capitol Police maintain order ahead of and during Joe Biden's inauguration with the overall amount of security expected to be nearly doubled over fears of a possible new wave of protests from Trump supporters not recognising the Democrat's election victory.
A report by AP suggested that the Pentagon had also directed the FBI to vet all security details for Joe Biden's inauguration amid fears of a possible "insider" attack or some other threat to the president-elect. These fears were triggered by allegations that some members of the Capitol Police had helped the rioters storm the Congress building on 6 January.