In this Jan. 19, 2021 photo, riot fencing and razor wire reinforce the security zone on Capitol Hill in Washington.  The…
FILE - Riot fencing and razor wire reinforce the security zone on Capitol Hill in Washington, Jan. 19, 2021.

Donald Trump supporters, who launched a deadly assault on the U.S. Capitol last month, have indicated they want to "blow up" the building and kill members of Congress, the acting chief of the Capitol Police said Thursday. 

Threats suggest extremists could target the building during an address by President Joe Biden, Acting Chief Yogananda Pittman told lawmakers as she advocated for continued high security around the building. 

"Members of militia groups that were present on January 6 have stated their desires that they want to blow up the Capitol and kill as many members as possible with a direct nexus to the State of the Union," Pittman told members of the House Appropriations Committee. 

FILE - National Guard personnel and police secure a street near the Capitol, Jan. 17, 2021.

"We think that it's prudent that Capitol Police maintain its enhanced and robust security posture until we address those vulnerabilities going forward," she said. 

A date has not been announced for Biden to deliver his address to Congress, which typically happens early in the year. 

Unprecedented security measures were imposed in Washington following the deadly January 6 assault on the U.S. Capitol, including fences topped with razor wire and checkpoints manned by the National Guard. 

About 5,000 troops are expected to stay through mid-March. 

Trump supporters stormed the Capitol in an attempt to stop Congress from certifying Democrat Joe Biden's electoral victory over the Republican president, who falsely claimed the November election had been marred by widespread fraud. 

The attack delayed the certification of Biden's win by several hours, as lawmakers were forced to flee the mob. Five people died in the violence, including a Capitol Police officer. 

More than 200 people have been charged for their roles in the riot, including some with ties to far-right fringe groups such as the Oath Keepers and Proud Boys.