Washington, D.C., was locked down and U.S. law enforcement officials geared up for pro-Trump marches in all 50 state capitals this weekend, erecting barriers and deploying thousands of National Guard troops to try to prevent the kind of violent attack that rattled the nation on Jan. 6.
The FBI warned police agencies of possible armed protests outside all 50 state capitol buildings starting Saturday through President-elect Joe Biden's inauguration on Jan. 20, fueled by supporters of President Donald Trump who believe his false claims of electoral fraud.
Michigan, Virginia, Wisconsin, Pennsylvania and Washington were among states that activated their National Guards to strengthen security. Texas closed its Capitol through Inauguration Day.
In downtown Washington, officers arrested a Virginia man who tried to pass through a Capitol Police checkpoint on Friday carrying fake inaugural credentials, a loaded handgun and more than 500 rounds of ammunition, CNN reported on Saturday citing a police report and a law enforcement source.
Capitol Police officials could not immediately be reached for comment.
Responding to news of the arrest, Democratic U.S. Representative Don Beyer of Virginia said the danger was real and the city was on edge. "Anyone who can avoid the area around the Capitol and Mall this week should do so," Beyer wrote on Twitter.
Steve McCraw, director of the Texas Department of Public Safety, said in a statement late Friday that intelligence indicated "violent extremists" may seek to exploit planned armed protests in Austin to "conduct criminal acts."
The scramble followed the deadly Jan. 6 attack on the U.S. Capitol in Washington by a mix of extremists and Trump supporters, some of whom planned to kidnap members of Congress and called for the death of Vice President Mike Pence as he presided over the certification of Biden's victory in November's election.
The Democratic leaders of four U.S. congressional committees said on Saturday they had opened a review of the events and had written to the FBI and other intelligence and security agencies to find out what was known about threats, whether the information was shared and whether foreign influence played any role.
"This still-emerging story is one of astounding bravery by some U.S. Capitol Police and other officers; of staggering treachery by violent criminals; and of apparent and high-level failures — in particular, with respect to intelligence and security preparedness," said the letter.
It was signed by House Intelligence Chairman Adam Schiff, House Homeland Security Chairman Bennie Thompson, House Oversight Chairwoman Carolyn Maloney and House Judiciary Committee Chairman Jerrold Nadler.
Law enforcement officials have trained much of their focus on Sunday, when the anti-government "boogaloo" movement flagged plans to hold rallies in all 50 states.
In Michigan a fence was erected around the Capitol in Lansing and troopers were mobilized from across the state to bolster security. The legislature canceled meetings next week, citing concern over credible threats.
"We are prepared for the worst but we remain hopeful that those who choose to demonstrate at our Capitol do so peacefully," Michigan State Police Director Joe Gasper told a news conference on Friday.
The perception that the Jan. 6 insurrection was a success could embolden domestic extremists motivated by anti-government, racial and partisan grievances, spurring them to further violence, according to a government intelligence bulletin dated Wednesday that was first reported by Yahoo News.
The Joint Intelligence Bulletin, produced by the FBI, Department of Homeland Security and National Counterterrorism Center, further warned that "false narratives" about electoral fraud would serve as an ongoing catalyst for extremist groups.
Thousands of armed National Guard troops were in the streets in Washington in an unprecedented show of force after the assault on the U.S. Capitol. Bridges into the city were to be closed, along with dozens of roadways. The National Mall and other iconic U.S. landmarks were blocked off into next week.
Experts say that the capitals of battleground states such as Wisconsin, Michigan, Pennsylvania and Arizona are among those at most risk of violence. But even states not seen as likely flashpoints are taking precautions.
Illinois Governor J.B. Pritzker said on Friday that while his state had not received any specific threats he was beefing up security around the Capitol in Springfield, including adding about 250 state National Guard troops.
The alarm extended beyond legislatures. The United Church of Christ, a Protestant denomination of more than 4,900 churches, warned its 800,000 members there were reports "liberal" churches could be attacked in the coming week.
Suzanne Spaulding, a former undersecretary for the Department of Homeland Security, said authorities disclosing enhanced security measures can be an effective deterrent.
"One of the ways you can potentially de-escalate a problem is with a strong security posture," said Spaulding, now a senior adviser at the Center for Strategic and International Studies. "You try to deter people from trying anything."
Following the Jan. 6 violence in Washington, some militia members said they would not attend a long-planned pro-gun demonstration in Virginia, where authorities were worried about the risk of violence as multiple groups converged on the state capital, Richmond.
Others told the Washington Post they wanted the protest organized in response to new state gun rules to be peaceful. Some militias across the country have told followers to stay home this weekend, citing the increased security or the risk that the planned events were law enforcement traps.