Rudy Giuliani tells ABC News he will not be part of President Donald Trump's legal team for the upcoming Senate impeachment trial.

“Because I gave an earlier speech [at the January 6 Trump rally before the Capitol riot],” Giuliani told ABC News Sunday night, “I am a witness and therefore unable to participate in court or Senate chamber.”

Trump was impeached by the House for the second time last week following the siege on the Capitol by a pro-Trump mob.

-ABC News' Jonathan Karl

The Delaware Humane Association hosted a virtual party with over 10,000 people to celebrate the first shelter dog moving into the White House.

While Champ and Major won't put their paws in the White House until Wednesday, the association held the fundraiser Sunday to celebrate the history being made: Major was adopted by Biden in March 2018.

"It means everything to us because it shines a light on the work we do," Delaware Humane Association's executive director Patrick Carroll said Sunday during the virtual party. "It shows that shelters are a wonderful place to adopt."

The shelter showed off photos of Major during his stay there in 2018 along with video of him and the president-elect. It also revealed dog "secretaries" which were dogs from its shelter that were selected by fans.

The Delaware Humane Association raised over $100,000, according to its host.

Biden's two German shepherds will also be the first dogs to live in the White House in four years, though Champ is no stranger to Washington. The Biden family brought the dog into their home in 2008 and he resided with them during his two terms as vice president.

The National Security Agency confirmed to ABC News that Michael Ellis has been named to be the agency’s new general counsel.

Ellis, who is considered to be a Trump loyalist, was pre-selected for the job, but his placement was slow-rolled by NSA Director Paul M. Nakasone.

Acting Defense Secretary Chris Miller demanded the NSA to put him in the career civil service job by 6 p.m. Saturday night, according to a source.

"Mr. Ellis accepted his final job offer yesterday afternoon. NSA is moving forward with his employment," an NSA spokesperson said in a statement provided to ABC News.

The Washington Post first reported the installation.

The NSA’s general counsel is a career civil service position and not an appointee position. Anyone in that post would continue on regardless of a change in administrations. They could only be removed under the same guidelines in place for other civil servants. There is a probationary period and tenure policy in place.

-ABC News' Luis Martinez

A Virginia man has been arrested near the Capitol while in possession of a gun, according to authorities.

Gordonsville resident Guy Berry, 22, was arrested at 12:15 a.m. on the 200 block of Massachusetts Avenue, the police report states. He was allegedly in possession of three high capacity magazines and 37 rounds of unregistered ammunition, police said.

Berry was charged with carrying a pistol without a license, possession of a large capacity magazine and unregistered ammunition.

-ABC News’ Jack Date

Addressing the coronavirus pandemic, confronting the climate crisis and building public trust in science and technology will be among the Biden administration's key areas of focus, the president-elect said during a press briefing introducing four key members of his science team.

Building back the economy "to ensure prosperity is fully shared all across America" and ensuring the U.S. "leads the world in technologies and industries that the future" will also be a focus, Biden said Saturday during an address in Wilmington, Delaware.

Helping lead those initiatives will be Eric Lander, the presidential science advisor-designate, a position that for the first time will be a cabinet rank, Biden noted.

"I've always said that the Biden-Harris administration will lead with science and truth," Biden said. "We believe in both. This is how we're going to, God willing, overcome the pandemic and build our country back better than it was before. That's why for the first time in history, I'm going to be elevating the presidential science advisor to a Cabinet rank, because we think it's that important."

Frances Arnold and Maria Zuber will be at the helm of the first all-women team to lead the President’s Council of Advisors on Science and Technology.

Alondra Nelson will also be deputy director for science and society for the Office of Science and Technology Policy.

Dr. Francis Collins, who was not present at the event, will also continue in his role as director of the National Institutes of Health.Biden thanked him for "being willing to stay on," saying that it wasn't his original plan.

"I've known Dr. Collins for many years. I worked with him closely," Biden said, accling him "brilliant, a pioneer, a true leader."

"This is the most exciting announcement that I have gotten to make in the entire Cabinet," Biden said of his picks. "These are among the brightest, most dedicated people, not only in the country but the world."