The former officials reportedly said the departures could pose serious risks to USA national security during an already rocky transition period.

According to ABC, an internal Federal Bureau of Investigation bulletin said that armed protests are being planned at all 50 state capitals and at the U.S. Capitol.

Wolf condemned the violence in a statement last week, and President Donald Trump subsequently pulled his nomination for a permanent role overseeing the Department of Homeland Security.

His move comes nine days ahead of President-elect Joe Biden's inauguration amid widespread fears about security in the aftermath of a pro-Trump mob's attack on the Capitol last week.

"On 8 January, the FBI received information on an identified group calling for others to join them in "storming" state, local and federal government courthouses and administrative buildings in the event POTUS is removed as President prior to Inauguration Day".

"Now that it happened people will take it much more seriously", the official said, referring to last week's violence.

In a statement released on Monday, Acting Homeland Security Secretary Chad Wolf said that "in light of events of the past week and the evolving security landscape leading up to the inauguration" he had instructed the Secret Service to begin security operations on Jan 13, instead of Jan 19.

Acting Homeland Security secretary Chad Wolf is stepping down, citing recent court challenges to his authority. In keeping with crowd size restrictions to slow the spread of the virus, traditional activities like the parade and the inaugural balls will be virtual.

In his last message before Twitter banned Trump, he said he would not be attending.

It will be one of Biden's first acts as president, and a show of bipartisanship at a time when the national divide is on stark display.

The Park Service said it would suspend tours of the Washington Monument, an obelisk honoring the country's first president, through Jan 24 due to safety concerns from threats to disrupt the inauguration. But plans were still on for a major public art display spanning multiple blocks of the National Mall that will feature 191,500 United States flags and 56 pillars of light. The display will include thousands of US flags, flags for every state and territory, and 56 pillars of light in similar representation. However, when the Biden campaign started sending out inauguration fundraiser packages to potential donors in the middle of December 2020 the biggest lot was $500,000 for private individuals and $1,000,000 for companies, which would grant the respective entity chair status for the inaugural events.

In keeping with the theme of unity, the committee also announced that after he is officially inaugurated, Biden, vice-president-elect Kamala Harris and their spouses will lay a wreath at the Tomb of the Unknown Soldier in Arlington National Cemetery.

At least one lawmaker asked the Pentagon to do more.