Sen. Lisa Murkowski, R-Alaska, confirmed that she met in person with Neera Tanden to discuss her nomination to serve as director of the Office of Management and Budget, but said she remains undecided on whether she would vote in Tanden's favor.

“I am still doing my assessment,” she said when asked repeatedly if she would support the nominee.

She also said she has “some more follow-up questions but we had a good conversation.”

Tanden's confirmation came into question last month, when Sen. Joe Manchin, D-W.Va., announced that he would break with his party and vote against Tanden's nomination, citing past tweets with strong language critical of Republican members of Congress and Sen. Bernie Sanders, I-Vt., many of which were deleted prior to her nomination.

Since then, the list of moderate Republicans opposing Tanden for the role has grown and in the evenly divided Senate, she needs support from a Republican.

-ABC News' Allison Pecorin

The Senate Monday evening voted 64-33 to confirm Miguel Cardona to lead the U.S. Education Department.

Cardona led Connecticut schools as the state's commissioner of education, but also spent time as an elementary school teacher and school principal, according to the Connecticut Department of Education.

He was also the first Latino to serve as education commissioner in the state and was the youngest principal in the state, the Biden transition said when announcing his nomination.

-ABC News' Sophie Tatum

During Biden's virtual bilateral meeting with Mexican President Andrés Manuel López Obrador, he said they would be discussing the possibility of sending doses of the COVID-19 vaccine to Mexico.

Earlier Monday, however, White House press secretary Jen Psaki said it was not something the president was considering.

"The president has made clear that he is focused on ensuring that vaccines are accessible to every American. That is our focus," she said.

This is Biden's second bilateral meeting -- held spoke with Canadian Prime Minister Justin Trudeau last week.

Biden told López Obrador that it's "not by accident" that this was his second virtual bilateral meeting. In a major shift of tone from Trump, Biden made a point of saying Mexico is an equal. His remarks sought to establish a close relationship for himself that will recognize the failures of the past but move forward together.

"There’s a long and complicated history between our nations. They haven't always been perfect neighbors with one another, but what we have seen over and over again the power and the purpose when we cooperate. And we're safer when we work together, whether it's addressing the challenges of our shared border or getting this pandemic under control," Biden said.

-ABC News' Sarah Kolinovsky

Sens. Chris Van Hollen, D-Md., and Martin Heinrich, D-N.M. wrote a letter Monday urging the Biden administration COVID response team to consider a new vaccine strategy that would prioritize first doses as the threat from variants, particularly the U.K. variant, increases.

The pair of Democratic lawmakers wrote to White House Coronavirus Response Coordinator Jeff Zients, "we encourage you to explore deploying existing second doses as first doses and rely on growing real-time inventory to cover future follow-on booster shots."

"We are not advocating for solely a single-dose regimen," the letter said. "Rather, we believe deploying existing second doses to cover more first doses—coupled with using real-time inventory in the coming weeks to serve as boost doses—would be the most societally beneficial choice and mitigate severe illness, hospitalization, and death.”

-ABC News' Trish Turner