By Priscilla Alvarez, Kevin Liptak and Geneva Sands, CNN

(CNN) -- President Joe Biden plans to nominate Tucson, Arizona, police chief Chris Magnus to serve as commissioner of US Customs and Border Protection and Ur Jaddou to serve as director of US Citizenship and Immigration Services, according to four sources familiar with the selections.

Jaddou has been widely speculated as the incoming head of USCIS, which oversees the US legal immigration system. She was formerly chief counsel at the agency under President Barack Obama and led the Biden-Harris Department of Homeland Security transition review team.

The announcements come days after Roberta S. Jacobson, a special assistant to the President and a key official dealing with the surge of migrants at the US-Mexico border, announced plans to leave at the end of April.

Also Monday, the White House unveiled several additional Department of Homeland Security nominations, including Jon Meyer for general counsel, Rob Silvers for under secretary for Strategy, Policy, and Plans and John Tien as deputy secretary.

If confirmed, Magnus will take the helm of the largest law enforcement agency and the second-largest revenue-collecting source in the federal government. He also served for 10 years as police chief for Richmond, California, and prior to that as police chief in Fargo, North Dakota, according to the department's biography.

Career official Troy Miller has led CBP, which has more than 60,000 employees, in an acting capacity since Biden took office in January.

"They are highly regarded and accomplished professionals with deep experience in their respective fields," Homeland Secretary Alejandro Mayorkas said in a statement.

CPB hasn't had a confirmed commissioner since Kevin McAleenan, who was tapped from the agency to serve as acting Homeland Security Secretary and eventually left the Trump administration.

Similarly, under the Trump administration USCIS was led by a string of acting officials after L. Francis Cissna left in 2019, most notably immigration hardliner Ken Cuccinelli.

Cuccinelli was the most prominent figure at USCIS during the Trump administration, gaining attention for his push on Trump policies and frequent press engagements.

As police chief in 2017, Magnus wrote a New York Times opinion piece criticizing the Trump administration's campaign against "sanctuary cities," writing that "Washington is trying to retaliate against them by withholding funding for things like crime prevention, drug treatment and mental health programs."

"When crime victims and witnesses are unwilling to testify because they're afraid an Immigration and Customs Enforcement agent will be waiting to arrest them at the courtroom doors, real criminals go unpunished," he wrote, slamming the Trump Justice Department for its policies and for "damaging police-community relationships and dismantling valuable public safety resources."

Obama-era CBP Commissioner Gil Kerlikowske praised the pick of Magnus. "He is an excellent leader, extremely thoughtful. He is exactly what CBP needs to lead the professionals in that organization. For too long they have had incendiary leadership more interested in Twitter and appearing on Fox News than managing and leading the organization," Kerlikowske told CNN.

This story has been updated with additional information.