President-elect Donald Trump has chosen South Dakota Gov. Kristi L. Noem (R) to serve as his homeland security secretary, picking another loyalist for a crucial role after he campaigned heavily on fortifying the border.

The selection was confirmed by people familiar with the choice who spoke on the condition of anonymity to discuss a decision not yet made public. Spokespeople for Trump's transition team and Noem did not respond to requests for comment.

As homeland security secretary, Noem would lead a sprawling federal bureaucracy with a $60 billion budget and more than 230,000 employees.

The role is key to Trump's domestic policy agenda, especially given his pledge to deport millions of undocumented immigrants and impose a crackdown at the U.S.-Mexico border. Noem is the latest high-profile choice related to border security that Trump has made since defeating Vice President Kamala Harris in the presidential election a week ago.

As well as customs, border and immigration enforcement, the Department of Homeland Security oversees the response to natural and man-made disasters, anti-terrorism work and cybersecurity. It also houses the Secret Service, which has been under scrutiny for months after the attempted assassination of Trump at a campaign rally this summer.

Trump took steps Monday toward his campaign promises to close the border to migrants and deport undocumented immigrants on a massive scale with two senior appointments to the incoming White House.

Trump announced that Tom Homan, former acting Immigration and Customs Enforcement director, would serve as "border czar," in charge of border security as well as deportations. Former speechwriter and campaign adviser Stephen Miller — who helped develop policies during Trump's first administration, including the ban on travel from Muslim-majority countries and the separation of families at the border — is expected to become a deputy chief of staff.

Noem, a farmer and rancher, has served as South Dakota governor since 2019. She previously served as the state's at-large member of Congress and in the state legislature.

She stood out early on in her governorship for refusing to implement restrictions related to the coronavirus pandemic.

Noem was initially viewed as a possible running mate for Trump in his comeback campaign. But her prospects seemed to dim after she recalled in a book published in May that she shot and killed a family dog because it was "untrainable" and aggressive.

The dog story caused a national uproar, with both Democrats and Republicans expressing unease. Noem defended the decision to kill the dog.

"We love animals, but tough decisions like this happen all the time on a farm," Noem wrote on X at the time.

Noem remained a campaign surrogate for Trump, who ultimately picked Sen. JD Vance (R-Ohio) as his vice-presidential candidate.

While South Dakota is more than 1,000 miles from the U.S.-Mexico border, Noem has sought to keep her state in the national spotlight when it comes to securing the southern border. She has sent South Dakota National Guard troops there, including one deployment that drew scrutiny because it was privately funded.

Noem has also echoed Trump's harsh rhetoric on illegal immigration, calling the situation at the border an "invasion." In South Dakota, Noem was banned from Native American reservations after making provocative comments about the impact of Mexican drug cartels on the communities.