Image source, Getty Images

Kristi Noem, 54, has led the US Department of Homeland Security (DHS) since Trump took office for his second term in 2025.

Noem has been at the helm of some of Trump's major campaign promises, including securing the US-Mexico border and mass deporting undocumented immigrants.

She's presided over the department during sweeping immigration crackdown across the country, and has been the face of it during some of its most controversial moments - the fatal shooting of US citizens Alex Pretti and Renee Good in Minnesota by federal agents earlier this year.

Before her role as homeland secretary, Noem was the governor of South Dakota from 2019 to 2025.

Noem is speaking now at conference in Nashville, Tennessee.

It's unclear if she knew about Trump's Truth Social post announcing her replacement before she took to the stage.

She's so far used the event to speak about her record on the border, the number of drug arrests she says the administration has made, and its efforts the lower murder rate

We'll bring you any key lines here.

Image source, Getty Images

US President Donald Trump says that Republican Senator Markwayne Mullin will replace Kristi Noem as Homeland Security Secretary from the end of March.

Mullin, a former professional Mixed Martial Arts fighter, has served as a US Senator for Oklahoma since 2023, following 10 years as a House Representative for the state.

His senate biography page describes him as a "business owner, working cow-calf rancher, and proud husband of 28 years" who has six children with his wife.

Bernd Debusmann Jr
Reporting from the White House

For those observing the ins and outs of Washington politics, today's announcement is no surprise - although it happened faster than some anticipated.

Just last night, I was talking to a source close to the Trump team that told me he believed Noem's replacement was "likely", although he added that Trump would probably wait a while to avoid seeming like he was responding to media pressure.

The US president had reportedly already been calling Republican lawmakers to feel out their responses, and a possible replacement.

Noem has been under intense scrutiny for months, particularly over her handling of the vast department and the aftermath of the deaths of two US citizens at the hands of federal agents in Minnesota earlier this year.

The final straw, however, appears to have been this week's fiery hearings on Capitol Hill, in which she claimed that Trump had approved of a multi-million ad campaign in which she featured.

In an interview with Reuters earlier today, Trump said that wasn't true.

"I never knew anything about it," he said.

We can bring you more now from Trump's statement on Truth Social.

The US president thanks Noem "for her service", before going on to praise Senator Markwayne Mullin for doing a "tremendous job representing the wonderful People of Oklahoma".

He describes Mullin as a "MAGA warrior" and praises him as a "former undefeated professional MMA fighter".

"Markwayne truly gets along well with people, and knows the Wisdom and Courage required to Advance our America First Agenda," he says, adding that Mullin "will work tirelessly" to keep the US borders secure.

US President Donald Trump has announced he is replacing Homeland Security Secretary Kristi Noem.

Noem, who has led Trump's immigration drive, will be replaced with Republican Senator Markwayne Mullin, Trump says.

"The current Secretary, Kristi Noem, who has served us well, and has had numerous and spectacular results," Trump said in a post on Truth Social.

He added that Noem will now shift to a newly established position, the Special Envoy for The Shield of the Americas, which Trump said was a "new Security Initiative in the Western Hemisphere"