A ring of reinforced fencing was erected around the US Capitol ahead of President Joe Biden's State of the Union address on Tuesday night, as Washington braces for protests by trucker convoys.

The barricades were initially installed following the events of January 6, 2021 when protestors stormed the Capitol in the wake of the election result, and remained in place for months before being removed.

Now steel fencing circles the Capitol once more amid fears that a convoy of US truckers will cause major traffic build up and engage in protests against pandemic restrictions as Biden gives his address.

Capitol Police chief Tom Manger said the fence is being put up 'out of an abundance of caution', in consultation with the Secret Service.

'In light of the upcoming State of the Union Address, and the possibility of demonstrations in the next couple of weeks,' Manger said in a statement, 'a plan has been approved to put up the inner-perimeter fence around the Capitol building for the State of the Union Address.'

He has also asked for assistance from the D.C. National Guard. And some streets around the four acre campus have been closed. 

Del. Eleanor Holmes Norton said she will 'ensure that the fencing comes down as soon as possible to restore freedom of movement for District of Columbia residents and the general public.' 

Capitol Hill staff were warned about the barricades and road closures. They were also told not to be alarmed at a heavy police presence when they came to work on Monday.

'For situational awareness, the D.C. National Guard and other state and local law enforcement and public safety agencies will be in the D.C. metropolitan area supporting the USSS, US Capitol Police, and the Metropolitan Police Department,' House Sergeant at Arms William J. Walker said in a note to staff on Sunday night.