President-elect Joe Biden is set to take the oath of office on January 20 on the same Capitol steps that were overrun by a mob of supporters of President Donald Trump on Wednesday.

Among those inside the Capitol complex were Vice President Mike Pence and President-elect Kamala Harris, who both are under Secret Service protection. Also, law enforcement had weeks to prepare for Wednesday’s events as Trump has been calling for his supporters to come to Washington to “Stop the Steal.”

The failure of law enforcement to contain the crowd will come under heavy scrutiny in the coming weeks, especially with Biden’s inauguration in 13 days.

Following an address by Biden on Wednesday, the president-elect addressed concerns of inauguration security.

“I am not concerned about my safety, security, or the inauguration. I’m not concerned. The American people are going to stand up, stand up now. Enough is enough is enough," Biden said.

Late Wednesday, Washington D.C. Mayor Muriel Bowser extended an emergency within the city through January 21, one day past Biden’s inauguration.

“Many persons came to the District armed and for the purpose of engaging in violence and destruction and have engaged in violence and destruction,” Bowser said announcing the order. “They have fired chemical irritants, bricks, bottles, and guns. They have breached the security of the Capitol and their destructive and riotous behavior has the potential to spread beyond the Capitol. Their motivation is ongoing. Today, they sought to disrupt the Congressional proceedings relating to the acceptance of electoral college votes. President Trump continues to fan rage and violence by contending that the Presidential election was invalid.”

Security forces in Washington, D.C., and state capitols across the country are on high alert Sunday as the country nears President-elect Joe Biden's inauguration.

The FBI has warned of indications that armed protests are being planned at all 50 state capitols and the U.S. Capitol in the days leading up to Jan. 20. A joint bulletin from the Department of Homeland Security, the FBI and eight other agencies says domestic extremists pose the most likely threat to the inauguration, particularly those who believe the incoming administration is illegitimate.

In response, the Pentagon has authorized up to 25,000 National Guard members for Inauguration Day in Washington, D.C., and much of the area surrounding the country's iconic political buildings has been fenced off or made inaccessible.

Similarly, state leaders across the U.S. ramped up security around their capitol grounds — pulling in National Guard members for help, erecting barriers, boarding up windows, asking residents to avoid the area and some even closing down capitol grounds altogether.

As of midday Sunday, the heavy security efforts dwarfed the mostly small protests taking place. In Michigan, a group of several dozen armed and armored demonstrators gathered in front of the state capitol in Lansing under a light snow. And in Ohio, a small group of protesters stood in front of the statehouse in Columbus near a large police presence and metal barriers, according to CNN affiliate WSYX.

Video: Small group demonstrates at Michigan Capitol

Meanwhile, capitols in Minnesota, Tennessee, California and Colorado, among others, had a major police presence but few if any protesters. In Oregon, five armed people dressed in camo and carrying flags arrived to the state capitol, saying they were anti-government libertarians who did not support either Biden or President Donald Trump.

The extent of any potential unrest remains unclear. After being banned from Twitter and Facebook, Trump has not promoted these gatherings. That's a contrast from his actions before the Jan. 6 rally in D.C., when he had repeatedly called for his supporters to converge on the city.

Still, online calls for violence have intensified recently. And experts warn the perceived success of the deadly insurrection earlier this month, when a pro-Trump mob overwhelmed police and took over the U.S. Capitol, may be motivation for another attack.

"As somebody who worked on al Qaeda-related terrorism throughout the 2000s at the Justice Department and worked extensively on counterterrorism investigations and cases, there were several times where we were anticipating a follow-on attack to a world event," Carrie Cordero, a CNN legal and national security analyst, said Saturday. "I have that same feeling now."

"It feels like there is a substantial threat that exists," Cordero added.

The heightened security, combined with the COVID-19 pandemic, is making for an Inauguration Day unlike any other.

DC mayor urges Americans to watch inauguration from home

In a fortified Washington, D.C., fences blocked off areas once open to the public, National Guard members patrolled near the Capitol and much of the city was closed to vehicles and street traffic.

The rehearsal for the inauguration ceremony will now be delayed until Monday amid heightened security concerns, acting Homeland Security Deputy Secretary Ken Cuccinelli said. Cuccinelli cited "online chatter" about the previously scheduled rehearsal day of Sunday but said there are "no specific credible threats."

Mayor Muriel Bowser urged Americans to enjoy the inauguration virtually from home and has asked anyone who does not need to be out to avoid restricted areas.

"Our goals right now are to encourage Americans to participate virtually and to protect the District of Columbia from a repeat of the violent insurrection experienced at the Capitol and its grounds on Jan. 6," Bowser said during a news conference Monday.

On Friday, U.S. Capitol Police arrested a Virginia man as he attempted to pass through a police checkpoint with unauthorized inaugural credentials, an unregistered handgun and more than 500 rounds of ammunition, according to court documents.

In an interview with the Washington Post, the man said he spent the past week working as hired security in Washington, D.C., and had been given credentials to guard media equipment. He told the Post he had forgotten that he had his firearm in his car when he left his home in Virginia, where he said he had a license to carry.

Because of concern over potential protests at state capitols, security measures are in place around the country. The U.S. Postal Service temporarily removed some mailboxes in several major cities, while the Transportation Security Administration said Friday it has "significantly increased its security posture."

The House Oversight Committee also sent letters Thursday to more than two dozen operators of bus lines, rental car companies and hotels asking for assistance in "identifying and preventing the ongoing and extreme threat of further violent attacks in Washington, DC, and elsewhere over the coming days."

The enforcement division of the Federal Communications Commission even warned the public against using radios as an alternative to social media to coordinate illegal activity. The warning says both explicit messages that facilitate a criminal act and "messages encoded for the purpose of obscuring their meaning" are prohibited.

Related video: Safety preparations ongoing at Massachusetts State House ahead of Inauguration Day

States closing, arming their capitols

Meanwhile, local and state leaders from coast to coast have boosted security for the coming days following officials' warnings of potentially more violence.

In Kentucky, Gov. Andy Beshear announced state capitol grounds will be closed entirely Sunday to "further ensure the safety of everyone -- both on or around the grounds and in the neighborhoods surrounding" the Capitol.

"Domestic terror is never OK," he said in a statement. "We must stop it every time we see it, and we cannot let what we saw at the U.S. Capitol become a new normal for this country."

Texas officials also said the state Capitol and its grounds will remain closed from Saturday to Wednesday, adding they were aware of "armed protests planned" and "violent extremists who may seek to exploit constitutionally protected events to conduct criminal acts."

Maryland Gov. Larry Hogan declared a state of emergency related to the inauguration, to allow the state to "more efficiently coordinate support and provide assistance" to its local jurisdictions and neighboring states, the governor's office said Friday.

Related video: Marylanders play crucial role in D.C. security for inauguration

Minnesota's leaders said Friday they're ready ahead of anticipated protests, noting there were no credible threats against the state Capitol.

"I want you all to be comfortable and assured that there has been nothing left undone to keep the capitol safe," Department of Public Safety Commissioner John Harrington said.

"We are not panicking," Lt. Gov. Peggy Flanagan added. "We are concerned, we are alert, and we are prepared."

In South Carolina, officials in the city of Columbia advised anyone who does not need to be in the city center, near the state's Capitol, to stay home.

"Unless there's a need, this weekend, and certainly on inauguration day, to be downtown," Mayor Stephen Benjamin said, "I encourage you to stay home."

The US Capitol Police announced Thursday that permanent fencing will be installed surrounding the Capitol building following the deadly Jan. 6 insurrection during the counting of Electoral College votes.

The permanent fencing comes one day after Homeland Security issued a warning about “domestic violent extremists” who may have become emboldened following this month’s attack of the US Capitol. Homeland Security warned that the Capitol and lawmakers will remain a target through early 2021.

“As I noted earlier this week, even before September 11, 2001, security experts argued that more needed to be done to protect the U.S. Capitol,” Yogananda D. Pittman, acting chief of the Capitol Police, said. “In fact, a 2006 security assessment specifically recommended the installation of a permanent perimeter fence around the Capitol.

“In light of recent events, I can unequivocally say that vast improvements to the physical security infrastructure must be made to include permanent fencing, and the availability of ready, back-up forces in close proximity to the Capitol.”

But Washington Mayor Muriel Bowser is objecting to the plan.

"Based on conversations with federal partners, there are some potentially volatile events upcoming that will require extra security. Fencing and the presence of troops will be a part of that. But we will not accept extra troops or permanent fencing as a long-term fixture in DC," Bowser tweeted. "When the time is right, the fencing around the White House and U.S. Capitol, just like the plywood we’ve seen on our businesses for too long, will be taken down."

Earlier this week, the National Guard confirmed to Scripps that 5,000 members of the Guard will remain stationed at the US Capitol.

Illustrating the tense law enforcement scene still unfolding at the US Capitol, Capitol Police said a male suspect attempted to unlawfully to enter the Capitol complex on Thursday. The Capitol Police claimed the man actively resisted arrest.

Earlier this week, the FBI said it has identified 400 suspects and conducted 135 arrests stemming from the Jan. 6 riot.

Five people died amid the violence after a mob of Trump’s supporters stormed the Capitol in an attempt to disrupt the counting of Electoral College votes. Among the deaths was a Capitol police officer who died a day after being assaulted. Dozens of other officers were injured in the ensuing melee.

Related video: Police will lead off panel's first Jan. 6 hearing

A Florida man who breached the U.S. Senate chamber carrying a Trump campaign flag is scheduled to become the first Jan. 6 rioter sentenced for a felony, in a hearing that will help set a benchmark for punishment in similar cases.

Prosecutors want Paul Allard Hodgkins to serve 18 months behind bars, saying in a recent filing that he, “like each rioter, contributed to the collective threat to democracy” by forcing lawmakers to temporarily abandon their certification of Joe Biden’s election victory and to scramble for shelter from incoming mobs.

Video footage shows Hodgkins, 38, wearing a Trump 2020 T-shirt, the flag flung over his shoulder and eye goggles around his neck inside the Senate. He took a selfie with a self-described shaman in a horned helmet and other rioters on the dais behind him.

His sentencing Monday in Washington could set the bar for punishments of hundreds of other defendants as they decide whether to accept plea deals or go to trial. Hodgkins and others are accused of serious crimes but were not indicted, as other were, for roles in larger conspiracies.

A lawyer for Hodgkins, who pleaded guilty last month to one count of obstructing an official proceeding, asked U.S. District Judge Randolph Moss not to impose a prison sentence, saying the shame that will attach to Hodgkins for the rest of his life should be factored in as punishment.

“Whatever punishment this court may provide will pale in comparison to the scarlet letter Mr. Hodgkins will wear for the rest of his life,” Patrick N. Leduc wrote in a recent filing, citing a Nathaniel Hawthorne novel in which a woman accused of adultery is forced to wear a letter “A.”

The filing argues that Hodgkins' actions weren’t markedly different from those of Anna Morgan Lloyd — other than Hodgkins stepping onto the Senate floor. The 49-year-old from Indiana was the first of roughly 500 arrested to be sentenced. She pleaded guilty to misdemeanor disorderly conduct and last month was sentenced to three years of probation.

Hodgkins was never accused of assaulting anyone or damaging property. And prosecutors said he deserves some leniency for taking responsibility almost immediately and pleading guilty to the obstruction charge, which carries a maximum 20-years prison sentence.

But they also noted how he boarded a bus in his hometown of Tampa bound for a Jan. 6 Trump rally carrying rope, protective goggles and latex gloves in a backpack — saying that demonstrated he came to Washington prepared for violence.

On the day, he walked through grounds already littered with smashed police barriers and broken windows, evening passing police officers and others injured as the crowd surged toward the Capitol, prosecutors said.

“Time and time again, rather than turn around and retreat, Hodgkins pressed forward,” the government filing said.

Leduc described his client as an otherwise law-abiding American who, despite living in a poorer part of Tampa, regularly volunteered at a food bank. He noted that Hodgkins had been an Eagle Scout.

His actions on Jan. 6 "is the story of a man who for just one hour on one day lost his bearings ... who made a fateful decision to follow the crowd,” the attorney said.

Leduc’s 33-page presentencing filing devotes several pages to the Civil War, highlighting Abraham Lincoln’s calls for reconciliation weeks before his assassination.

“The court has a chance to emulate Lincoln,” he wrote.