White House Press Secretary Jen Psaki held a wide-ranging briefing with reporters Tuesday in which she addressed bipartisan negotiations on COVID-19 following Biden's two-hour meeting with GOP senators in the Oval Office Monday and his latest immigration executive actions.

When ABC News' Senior White House Correspondent Mary Bruce asked about the realistic opportunity for compromise on relief legislation, Psaki said there are some "bottom lines" Biden will not budge on.

On Biden's immigration executive orders expected later Tuesday, Psaki responded to Bruce, who raised the criticism that the orders initiate "reviews" of Trump's most restrictive policies rather than recalling them. Psaki argued the administration needed to see where things stand first to move forward.

“Part of our effort, Mary, is to assess the damage that has been done by the policies that were put in place by the prior administration. We want to act swiftly. We want to act promptly, but we also need to make sure we're doing that through a strategic policy process,” she said.

Psaki also promised a review within 120 days and every 60 days after on the progress the administration is making on reuniting families that were separated at the Southern border.

“We need to find out first where all these kids are and figure out where their parents are. And so, we're starting at, you know, square one here, but our team wants to ensure that we are providing an update on what progress is being made,” Psaki added.

Later in the briefing, she admitted part of the administration’s work is to determine exactly how many children have been separated from their families. She couldn’t confirm whether the number is closer to 600 or 1,600.

-ABC News' Molly Nagle and Sarah Kolinovsky

The U.S. Senate narrowly voted to confirm Alejandro Mayorkas, Biden's pick to lead the Department of Homeland Security in a 56-43 vote Tuesday afternoon.

Senate Majority Leader Mitch McConnell voted against his confirmation, citing a 2015 inspector general report that raised questions about Mayorkas' actions in his former role at DHS.

A former federal prosecutor and deputy DHS secretary, Mayorkas is the first Latino and first immigrant to lead the department tasked with enforcing the country's immigration policies.

He faces an increasing challenge at the border and at home as he takes over a department that hasn't had a confirmed secretary in more than two years.

He also enters the department as it faces a national security threat in homegrown domestic extremists -- an issue Mayorkas vowed to combat at his confirmation hearing.

-ABC News' Luke Barr

In response to the last-minute appointments to Defense Department boards of loyalists to former President Donald Trump, like Corey Lewandowski and others, Defense Secretary Lloyd Austin has ordered the suspension of the activity of the Pentagon’s 42 civilian advisory boards while a “zero-based review” -- or top-to-bottom review -- of each board is carried out, according to a senior defense official.

While the review will streamline the potential overlap of many boards, the official acknowledged that the review was driven by Austin’s concerns about the last-minute appointments.

“The secretary was deeply concerned with the pace and the extent of recent changes to memberships of the department advisory committees done with a bit of frenetic activity in the final two months of the previous administration,” said the official. “It gave him pause to consider the broad scope and purpose of these boards and and to think about how they can best be aligned and organized and composed to provide competent technical professional, policy advice to the department.”

The official said that each board will have until February 16 to suspend its activities and then the board’s “sponsor” will have until April 30 to review who should be a member of the board, and whether it is viable by aligning with the National Defense Strategy. By June 1, the Pentagon will make its decisions.

The move will affect hundreds of individuals appointed to serve on the boards but not those appointed by a president or Congress. That means former White House press secretary Sean Spicer, for example, who was appointed by Trump in 2019 to serve at the Naval Academy’s board of visitors, will not be affected. Once the review is finished, individuals will be renominated to positions by the secretary of defense or the board’s sponsors.

Addressing the notion that the move will be seen as a Trump purge, the official said that Austin believes the process of suspension and review is “the most equitable, fair, and uniformly consistent way to do it across the department.”

-ABC News' Luis Martinez

Jeff Zients, the White House coordinator on COVID-19, announced on Tuesday that starting next week, the government will begin shipping a small number of coronavirus vaccine doses directly to select pharmacies across the country.

Zients said 1 million doses will go to 6,500 pharmacies on Feb. 11 on top of the 10.5 million doses that will be delivered next week to states for distribution. He said more doses will continue to reach pharmacies as the program expands with time.

The allocation will be based on population, but Zients said the government is making sure to reach pharmacies "in areas that are harder to reach to ensure that we have equitable distribution.”

The initial number of pharmacies to receive doses -- 6,500 -- represents a small number of the 40,000 pharmacies nationwide.

Additionally, people receiving a shot through pharmacies will still have to meet their state’s eligibility requirements.

“I wanted to set expectations appropriately,” Zients told reporters in a Zoom call Tuesday. “Due to the current supply constraints, this will be limited when it begins … In the early phase, many pharmacies across the country will not have vaccine, or may have very limited supply."

-ABC News' Anne Flaherty