Noem's firing comes after a controversial tenure at DHS with nationwide protests, a partial government shutdown and a divisive ad campaign.

Oklahoma Republican Sen. Markwayne Mullin says he has no idea how quickly his nomination to replace Kristi Noem at the Department of Homeland Security will move

The announcement comes amid criticism of DHS spending under Noem, and as Congress has allowed the department's funding to lapse.

U.S. Senator Markwayne Mullin (R-OK), tapped by U.S. President Donald Trump to replace U.S. Homeland Security Secretary Kristi Noem, gets into his car as he departs the U.S. Capitol after a vote in the U.

Democratic lawmakers said Stephen Miller and Pam Bondi should be next after President Donald Trump announced Kristi Noem would be stepping aside as DHS secretary.

President Trump tapped Oklahoma Sen. Markwayne Mullin as the next Secretary of Homeland Security, replacing Kristi Noem.

President Donald Trump on Thursday announced he was ousting Department of Homeland Security Secretary Kristi Noem, and that GOP Sen. Markwayne Mullin of Oklahoma would replace her.

President Donald Trump has removed Homeland Security Secretary Kristi Noem from her post overseeing the administration's immigration enforcement, saying she will transition to a new security initiative.