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Authorities in Washington, DC, are bracing for more extremist violence in the coming days after supporters of President Trump stormed and breached the US Capitol last week in a deadly riot that left five people dead.

Federal law enforcement agencies have issued an urgent call for assistance in securing the nation’s capital as the inauguration nears, CNN has reported, warning that domestic extremists are likely more emboldened to carry out attacks on Biden’s inauguration and throughout 2021 after seeing the success of the US Capitol.

More than 20,000 National Guard troops could be in Washington to help secure Biden’s inauguration, Washington Police Chief Robert Contee said Wednesday, and sources tell CNN that officials are considering raising the terrorism threat level.

The National Mall, meanwhile, will be closed to the general public on Inauguration Day due to security concerns, according to an official familiar with discussions.

The official said there will be no big screens, no toilets and no panels were people stand, and the public will not be able to get down to the mall where traditionally thousands gather to watch the new President be sworn in.

President-elect Joe Biden’s advisers, who are helping plan the inaugural, say it is intended to be a virtual event. They did not object to heightened security restrictions recommended by authorities pertaining to the Mall or the area surrounding the White House.

There are ongoing discussions between the District of Columbia, National Park Service and the US Department of Interior on when the shutdown will happen. There won’t be access on Jan. 20, but when exactly before that is still the subject of discussion.

The National Park Service said in a statement an announcement would be made by the department or the United States Secret Service when a final decision was made.

The restrictions on the National Mall were first reported by the Washington Post.

The President-elect and Vice President-elect Kamala Harris are still expected to take their oaths of office on the West Front of the US Capitol during a significantly scaled-down event. Biden said this week that he was “not afraid of taking the oath outside” and that his team had been receiving briefings in the wake of the violence.

On Wednesday, Biden received a briefing from senior officials at the FBI, the Secret Service and key members of his national security team about the potential for additional extremist violence in the coming days, according to the President-elect’s transition team.

See the security precautions around the Capitol: