WASHINGTON, United States, Dec 12, 2025 (BSS/AFP) - Democratic lawmakers called for US Homeland Security chief Kristi Noem's resignation Thursday as she defended the Trump administration's mass deportation program at a fiery congressional hearing.

"You promised America that you would go after the worst of the worst," Democratic Representative Seth Magaziner said.

But the vast immigration crackdown launched under Republican President Donald Trump has swept up veterans of the US military, their relatives, pregnant women, children and even some American citizens, Magaziner said.

"There are many problems with your leadership but the biggest problem is this: You don't seem to know how to tell the difference between the good guys and the bad guys," he told the House Homeland Security Committee hearing, which was interrupted by demonstrators on several occasions.

The panel's ranking Democrat Bennie Thompson said Noem has "diverted resources from critical Homeland Security agencies and programs to carry out an extreme immigration agenda."

"Black and brown Americans in particular, have been racially profiled, detained and locked up," Thompson said.

"So rather than sitting here and wasting your time and ours with more corruption, lies and lawlessness, I call on you to resign," he said, echoing a call Democrats have made for months as ICE has raided major cities.

In June, after Senator Alex Padilla was tackled and cuffed at a press conference Noem held in Los Angeles, Senator Elizabeth Warren and others demanded she step down.

- Noem defends tactics -

In Thursday's hearing, Representative Delia C. Ramirez told Noem "your options are limited. Either you're going to resign, Trump's going to fire you, or you will be impeached."

Ramirez, who represents the midwestern city of Chicago which has seen numerous ICE raids, also made a formal request for the House Judiciary Committee to open an investigation into Noem's "unlawful and potentially impeachable actions."

While Democrats lambasted Noem and the Trump administration, Republicans praised her department for securing the US-Mexico border and rounding up undocumented migrants for deportation.

Noem defended the tactics of Immigration and Customs Enforcement (ICE) agents and accused the administration of Democrat Joe Biden of allowing "millions of people to come into our country illegally."

She denied US citizens have been detained although she said there have been occasions when they were held until their identity could be confirmed.

"We have never once detained or deported an American citizen," Noem said.

"(When) we are doing our targeted enforcement operations against criminal illegal aliens, individuals that are in that area may be detained until we verify who they are, and then they are released."

Trump ran for the White House promising to deport millions of undocumented migrants and Noem, as head of the Department of Homeland Security, oversees the operation.