Watch Live: Kristi Noem, Trump's pick for homeland security ...

Washington — South Dakota Gov. Kristi Noem, President-elect Donald Trump's pick to lead the sprawling Department of Homeland Security, is fielding questions from lawmakers on Friday at her Senate confirmation hearing.

She is appearing before the Senate Homeland Security and Governmental Affairs committee, which has jurisdiction over the DHS and those nominated to lead the department.

"As we face the evolving threats of the 21st century, the mission and the success of DHS is more critical than ever. We must be vigilant and proactive and innovative to protect the homeland," she said in her opening statement. "The challenges in front of us are extremely significant, and we must secure our borders against illegal trafficking and immigration."

Noem, a former Republican member of Congress who has been South Dakota's governor since 2019, was expected to be asked about the incoming Trump administration's sweeping immigration plans, which include a promised mass deportation operation.

DHS oversees airport security, the U.S. Coast Guard, the Federal Emergency Management Agency and other responsibilities. The queston of FEMA funding came up early in the hearing when Democratic Sen. Richard Blumenthal of Connecticut raised the California wildfires. He expressed dismay about Trump's comments about the fires — and the state's Democratic governor, Gavin Newsom. He noted the president-elect said recently, "We won't give him, referring to Gov. Newsom, money to put out fires, and if we don't give him money, he's got a problem," and asked Noem if she would say "no" to Trump if he tried to withhold aid to California or any other state for political reasons.

While Noem did not address the question about Trump, she assured Blumenthal, "Under my leadership of the Department of Homeland Security, there will be no political bias to how disaster relief is delivered to the American people."

"I will deliver the programs according to the law, and it will be done with no political bias," she said.

The department also houses the three main federal immigration agencies that will play a key role in implementing Trump's immigration agenda: U.S. Citizenship and Immigration Services, Customs and Border Protection and Immigration and Customs Enforcement.

When announcing her nomination as DHS secretary soon after the election, Trump noted that Noem dispatched the South Dakota National Guard to the U.S.-Mexico border to help Texas state officials fortify it amid record levels of migrant crossings.

If confirmed as DHS secretary, Noem would likely play an important role in shaping the second Trump administration's planned changes to U.S. immigration and border policy, alongside incoming border czar Tom Homan and deputy chief of staff Stephen Miller. Republicans control a majority in the Senate, making her confirmation likely.

During the hearing, GOP senators asked Noem about an app introduced by the Biden administration, called CBP One, to allow migrants to set up an appointment at international bridges, where U.S. officials determine whether they should be allowed into the country to request asylum. It's been used millions of times to help process claims more quickly. Many Republicans oppose its use and asked about Noem's plans for the app.

"Will you use your authority to stop facilitating faster processing of illegal aliens into our country with the CBP One app," GOP Sen. James Lankford of Oklahoma asked.

"Yes, Senator," Noem responded. "We will eliminate the CBP One app — maintain some of the data that's in it that's critical to knowing who's in our country — but that app will no longer be in use."

Among other promises, Trump and his advisers have vowed to reverse Biden administration immigration programs, enact harsher rules at the U.S.-Mexico border, scale back refugee admissions and dramatically ramp deportations of immigrants living in the country illegally. The president-elect has also pledged to upend the longstanding principle of birthright citizenship, in a bid to prevent children born to unauthorized immigrants from becoming American citizens at birth. 

Considered a Trump loyalist, Noem has been praised by conservatives for her record as governor, which includes vocally opposing mask mandates and other COVID-era measures. But she's also garnered detractors. Tribal nations in South Dakota, for example, have banned her from their lands over comments she's made alleging cartel activity in tribal territory.

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Camilo Montoya-Galvez

Camilo Montoya-Galvez is the immigration reporter at CBS News. Based in Washington, he covers immigration policy and politics.