On Wednesday next week, incoming President Joe Biden will be installed.
Massive work is now underway to increase security ahead of the ceremony.
"We are taking a closer look at people who may be planning to repeat the kind of violence we saw last week," FBI Director Christopher Wray told Reuters.
"Will find you"
Large areas around the White House will be shut down and more than 20,000 troops are expected to be in Washington DC on January 20, US media reports.
Subway stations will be shut down in the capital, and several U.S. airlines announced Thursday that they will stop travelers flying to airports in and around Washington DC from checking in weapons.
- We have already identified over 200 suspects from January 6 alone.
So we know who you are, if you're out there, and FBI agents will find you, Christopher Wray said during a pre-installation security briefing.
More than 100 people have been arrested by the FBI on suspicion of involvement in the January 6 storm of Congress.
Pence: Safe installation
On Thursday, Vice President Mike Pence took part in his first public appearance since the storming of Congress, when he took part in a special rally on security planning ahead of January 20.
"We will ensure that a secure installation of incumbent President Joe Biden and incumbent Vice President Kamala Harris is carried out," Mike Pence was quoted as saying by Reuters.