Six days before the inauguration of President-elect Joe Biden, officials are tightening security in Washington, D.C., for what is expected to be a solemn ceremony shorn of the usual crowds following last week's deadly attack on the U.S. Capitol by supporters of President Donald Trump.

Law enforcement authorities say they are confident of maintaining safety during the event, despite warnings about further violence in Washington and around the country. The National Guard Bureau said Thursday that nearly 7,000 Guardsmen are already in the nation's capital and more are en route toward a planned deployment of up to 21,000 troops.

The Guardsmen will be backed by hundreds of federal agents and local and state police officers. Four years ago, the Guard deployed about 8,000 soldiers for Trump's inauguration.

"I'm confident these members of the Guard will assist in any way they can to help maintain peace and security in our nation's capital in the days ahead," Wisconsin Gov. Tony Evers said in a statement.

Wisconsin is mobilizing about 500 National Guard troops to assist with inauguration security in the Washington region.

Vice President Mike Pence speaks to National Guard troops outside the U.S. Capitol, January 14, 2021, in Washington. Alex…
Vice President Mike Pence speaks to National Guard troops outside the U.S. Capitol, Jan. 14, 2021.

After a briefing on inauguration security by top officials, Vice President Mike Pence said the ability of law enforcement agencies to protect "dozens and dozens" of events in Washington in the past "gives great encouragement to us and to any American that will be looking on today."

Pence thanked the FBI for aggressively pursuing those responsible for the attack on the U.S. Capitol last week. The FBI has arrested dozens of people in connection with the rioting and expects more arrests in the coming weeks.

Unprecedented security measures

With police shutting down a large section of downtown Washington on Wednesday, six days earlier than originally planned, the normally busy streets leading to the Capitol emptied of cars and tourists on Thursday, while construction crews continued to build security barriers and fencing ahead of the January 20 inauguration.

Workers install razor wire atop the unscalable fence surrounding the U.S. Capitol in the wake of the January 6th riot and ahead…
Workers install razor wire atop the unscalable fence surrounding the U.S. Capitol in the wake of the January 6th riot and ahead of the upcoming inauguration in Washington, Jan. 14, 2021.

The Capitol complex remained closed to the public. U.S. Capitol Police warned in a statement that anyone attempting to breach the grounds "will be subject to an appropriate use of force and arrest." The Secret Service, the federal agency leading the gargantuan security effort, said the street closures around the Capitol will go into effect immediately.

The security measures are unprecedented. They come as the FBI warns of armed protests in Washington and all 50 state capitols starting this weekend. The January 6 rampage on the U.S. Capitol left five people dead, including a police officer, as Capitol Police, outnumbered by the rioters, failed to fend off the attack.

Workers board up the buildings near the White House prior to the presidential inauguration in Washington, U.S., January 14,…
Workers board up buildings near the White House prior to the presidential inauguration in Washington, Jan. 14, 2021.

The attack on the Capitol "impacted the way we are approaching working with our federal partners in planning for the 59th inauguration," D.C. Mayor Muriel Bowser said Wednesday.

Dan Linsky, a former Boston police chief and now a managing director at the global risk consulting firm Kroll, said locking down central Washington was an "absolutely appropriate" step.

"We're living in different times, and we need to have different responses," Linsky said. "We need to evaluate the potential threats and make sure that we're having mitigation programs that can meet, prevent and overwhelm those threats."

Nationwide precautions

States across the country have also increased security in response to the FBI warning.

In Michigan, a six-foot fence will be installed around the Capitol that was stormed by protesters last week. "The state police have secured the Capitol, and I've got confidence that we will continue to be able to," Gov. Gretchen Whitmer said Wednesday.

In New York, state police said, "out of an abundance of caution," they have taken steps to harden security around the Capitol in Albany.