Security officials will soon scale back fencing that has circled the US Capitol and cut off the entire area to pedestrians and vehicles since a mob attacked the building on January 6.

Timothy Blodgett, the acting House serjeant-at-arms, said in a memo to members of Congress that the fencing would be pulled down in two phases in response to guidance from the Capitol Police that “there does not exist a known, credible threat” that warrants keeping the temporary barrier in place.

In a letter to colleagues, House Speaker Nancy Pelosi said the Capitol Police would “continue to monitor the threat posture, and plans will be adjusted if and as needed”.

How to protect lawmakers, while keeping the Capitol grounds open to visitors, has emerged as one of the more daunting questions from the deadly insurrection in the dying days of Donald Trump’s presidency.

Democrat and Republican lawmakers have decried the fencing as unsightly, expensive and beyond what is necessary, even though security fears remain high.

Members of Congress have described their unease at arriving for work each day in what can feel like a war zone, with checkpoints and National Guard troops lining the perimeter fence.

The absence of tourists snapping photos of the Capitol dome or constituents meeting representatives was an emotional loss on top of coronavirus restrictions, they said. The security perimeter extends far beyond the Capitol itself through neighbouring parks and office buildings.

The fencing and other defences were installed after the deadly January 6 riot.

Lawmakers are also debating whether to launch a bipartisan commission to study the massive security failures that occurred on January 6 and how to respond to them in the long term.

On Monday (local time), Ms Pelosi released a draft proposal for a commission that Republicans rejected in February, writing to colleagues that “we must get to the truth of how the January 6 assault happened, and we must ensure that it cannot happen again”.

Five people died after protesters stormed the building trying to stop Congress from certifying Democrat Joe Biden’s election over Republican Mr Trump. Mr Trump was impeached by the House for inciting the mob, then acquitted by the Senate.