The danger to the public and to law enforcement officers from explosive devices during expected upcoming protests "is substantial," the Federal Bureau of Investigation warned in a new awareness bulletin obtained by ABC News on Friday.

The document is full of photos of devices used in the last eight months against civilian and law enforcement targets during public demonstrations.

"Devices targeting infrastructure also increased following violent activity during this time period," the bulletin states.

The FBI now wants to make first responders aware of what has been deployed in the past and what they might encounter during protests linked to the presidential inauguration on Jan. 20.

"The danger posed to law enforcement officers and the general public from the all the tactics listed is substantial," the bulletin states. "If a suspicious item is reasonably believed to contain explosives, an IED, or other hazardous material, DO NOT touch, tamper with, or move the item. Only bomb disposal personal should handle any suspected devices that are located."

An internal FBI bulletin obtained by ABC News earlier this week stated that armed protests are being planned at all 50 state capitols as well as at the U.S. Capitol in Washington, least through Inauguration Day.

The warning comes after suspected pipe bombs were found last week outside both the Democratic National Committee and the Republican National Committee headquarters, just a few blocks from the Capitol where pro-Trump rioters stormed the building.

-ABC News' Aaron Katersky

Biden has chosen Dr. David Kessler, former commissioner of the Food and Drug Administration (FDA), to help lead the federal government's COVID-19 vaccine initiative.

Kessler, a pediatrician and lawyer who headed the FDA from 1999 to 1997 under the Bush and Clinton administrations, will replace Dr. Moncef Slaoui, who is the current chief science officer to Operation Warp Speed.

Biden also announced several other appointees who will join his incoming administration's COVID-19 response team.

"We are in a race against time, and we need a comprehensive strategy to quickly contain this virus," the president-elect said in a statement Thursday. "The individuals announced today will bolster the White House’s COVID-19 Response team and play important roles in carrying out our rescue plan and vaccination program. At a time when American families are facing numerous challenges I know these public servants will do all that is needed to build our nation back better."

With just five days until his inauguration, Biden announced Thursday his pick to head the Federal Emergency Management Agency (FEMA) along with several other key posts for his incoming administration.

Deanne Criswell is his nominee for FEMA administrator. Janet McCabe is his nominee for deputy administrator of the Environmental Protection Agency (EPA). Shalanda Young is his nominee for deputy director of the Office of Management and Budget. Jason Miller is his nominee for deputy director for management at the Office of Management and Budget. And David Cohen is his appointee for deputy director of the Central Intelligence Agency (CIA).

"These dedicated and distinguished leaders will bring the highest level of experience, integrity, and knowledge to bear on behalf of the American people," Biden said in a statement Thursday. "Each of them brings a deep respect for the civil servants who keep our republic running, as well as a keen understanding of how the government can and should work for all Americans. I am confident that they will hit the ground running on day one with determination and bold thinking to make a meaningful difference in people's lives."

Alex Padilla, California’s Secretary of State and the man who will fill Vice President-elect Kamala Harris’ seat in the Senate, told ABC News he’s prepared to balance both the impeachment trial and response to COVID-19 when he’s sworn in next week.

“We have to be able to walk and chew gum at the same time,” Padilla said. “It’s not either or, COVID-19 response is absolutely important. Holding President Trump accountable is extremely important. And doing our part, as the Biden-Harris administration settles, is also extremely important. So we're prepared to do what it takes.”

He said he doesn’t know how the Senate will vote, but believes a “rebalanced leadership” with Democrats in the White House, Senate and House, will give the party “tremendous opportunity” to achieve their goals.

When asked whether he believes last week’s riot at the Capitol would embolden further attacks, he said, “Frankly, when I saw the images last Wednesday, it only emboldened my resolve to want to get to work, and want to get to work quickly.”

-ABC News' Allie Yang

As procedural votes were underway in the House, Speaker Nancy Pelosi went outside the Capitol to thank the National Guard troops deployed to the complex in the wake of last week's riot and ahead of Biden's inauguration in one week.

Some National Guard members inside the Capitol were spotted taking in the sights of the Rotunda Wednesday morning, gathering around and listening to Rep. Brian Mast, R-Fla., an Army veteran who lost both legs in Afghanistan.

The Capitol has been closed to tours for months due to the coronavirus pandemic. With the exception of last Wednesday's attack, this is one of the few times visitors have snapped photos inside the building during the pandemic -- finding themselves with unique access as they've been designated to protect the building and lawmakers.

As lawmakers arrived on the Hill ahead of the House gaveling in to consider Trump's second impeachment, a heavy National Guard presence greeted them both outside and inside the building -- with some resting, embracing their rifles, on the floor of the Capitol.

Jane Campbell, the president and CEO of the United States Capitol Historical Society, confirmed to ABC News that troops have not been quartered in the Capitol since the Civil War -- when the Rotunda was still under construction, and the open-air space was used as a field hospital.

A Defense official said the National Guard members seen sleeping at the Capitol are on breaks and noted that it’s not uncommon on domestic or overseas deployments to see members taking breaks in between long shifts.

There are currently 6,600 members of the National Guard in Washington, D.C. with more continuing to flow in. A Defense official said Wednesday afternoon that the National Guard has now been authorized to have up to 20,000 Guardsmen in Washington for inauguration security and that most may be in town by this weekend.

-ABC News Luis Martinez and Benjamin Siegel