By Veronica Stracqualursi, CNN

(CNN) -- Rep. Ilhan Omar slammed a senior White House adviser as a "white nationalist" Monday on Twitter.

"Stephen Miller is a white nationalist," Omar, a Minnesota Democrat, wrote. "The fact that he still has influence on policy and political appointments is an outrage."

She pointed to reporting that Miller has been behind President Donald Trump's hardline immigration policies, convinced the President to drop his nominee to lead US Immigration and Customs Enforcement and go in a "tougher direction."

Omar's attack against Miller, who is Jewish, came as she has faced criticism of her own in recent weeks. One of the first two Muslim women in Congress, she has been accused of pushing anti-Semitic tropes, which prompted a rebuke from several House Democratic leaders.

Trump appears to be in the midst of cleaning house at the Department of Homeland Security. Over the past two days, Homeland Security Secretary Kirstjen Nielsen and Secret Service Director Randolph "Tex" Alles were ousted, and at least two other officials have been named as possibly heading out the door.

CNN reported that at least some of the sudden personnel changes came at the urging of Miller, who's been recently empowered by the President to lead the administration's border policies.

Miller was the author of Trump's controversial travel bans and the administration's "zero-tolerance" policy that was halted due to the backlash over thousands of undocumented children separated from their families at the border. He played a key role in Nielsen's Sunday resignation.

The staff shakeup appears to be indicative of the administration's attempts to redirect immigration policy following a surge of migrant apprehensions at the southern border in recent months.

Omar, one of the first two Muslim women in Congress, has been accused of pushing anti-Semantic tropes, which prompted a rebuke from several House Democratic leaders.