WASHINGTON - Well before the concrete blocks and double row of tall fences that ring the United States Capitol, National Guard troops with automatic weapons check vehicles.
They are under strict orders to take no chances.
The inauguration of former vice-president Joe Biden as the 46th president of the United States will take place amid the tightest security in living memory.
Referring to the storming of the US Capitol by a mob of Donald Trump supporters on Jan 6, Washington, DC Mayor Muriel Bowser told a press conference on Friday (Jan 15): "We saw white extremists storm the Capitol building who were trained and organised. We all have to think about a new posture."
That posture is to turn the heart of the Federal Government into a fortress, complete with militarised red and green zones - red for maximum restrictions.
"We continue to ask anyone who doesn't absolutely need to be out and about, or in those restricted areas, to avoid them," Mayor Bowser said.
So far, about 21,000 armed National Guard troops - the number may grow to 25,000 - have been deployed to lock down the capital ahead of the inauguration, which has been drastically reduced in size and scale because of the Covid-19 pandemic - and now the security concerns.
A large part of the historic National Mall is already closed. Some train Metro stations closed on Friday.
Across the country too, from Phoenix, Arizona in the south-west to Lansing, Michigan in the north-east, tall chain link fences have been erected around state Capitols.
The Federal Bureau of Investigation (FBI) has warned law enforcement agencies of planned rallies at all 50 state capitols as well as in Washington, DC on Sunday through to the inauguration next Wednesday.
Many of these will be armed protests. Michigan Governor Gretchen Whitmer, herself the target recently of a kidnap and murder plot by a group of white supremacists, foiled by the FBI, has activated the Michigan National Guard to help with security.
Law enforcement agencies are beefing up airport security and vetting airline passenger lists, as right-wing groups emboldened by the storming of the US Capitol answer calls to travel for protests. Some are planning to turn up armed.
The Transportation Security Administration (TSA) is increasing the number of federal marshals on flights and explosive-detection dogs at airports, the New York Times reported.
And security experts are warning that the violent storming of the Capitol by Trump supporters may be just the beginning of more conflict, and well beyond next week.
"Massive quantities of weapons have been exchanging hands on public forums and in response to a prospective insurrection," security analyst Malcolm Nance told a Congressional hearing on Wednesday.
"This is only the beginning," he said, predicting that post-Trump presidency, the conflict will "transition into an active insurgency".
Separately Mr Ali Soufan, chairman and chief executive officer of the global security consultancy Soufan Group, on Thursday said white supremacists have been "allowed to operate and function with... impunity and the chickens are coming home to roost".
"This is not only about the people who attacked (the Capitol) but about the network that allowed them to operate so openly... that now they are actually, literally, threatening 50 capitals in the United States," he told a virtual forum. "You have to target the network."
During a press conference on Tuesday, acting US Attorney Michael Sherwin said prosecutors looking into the Capitol riot are treating the matter as a "significant counter-terrorism or counter-intelligence investigation" involving probes into "money, travel records, disposition, movement, communication records".
Four government agencies have launched their own investigations into the Jan 6 insurrection as well.
One additional factor causing concern, is the number of active or former police or military involved in storming the Capitol. Several groups acted with military-like intent and coordination.
The Pentagon's internal watchdog on Thursday said it would investigate whether the US Department of Defence (DoD) has adequate procedures in place to prevent white supremacists and other extremists from joining and remaining in the military.
"Our objective is to determine the extent to which the DoD and the Military Services have implemented policy and procedures that prohibit active advocacy and active participation related to supremacist, extremist, or criminal gang doctrine, ideology, or causes by active duty military personnel," the Inspector General's office of the DoD said.