WASHINGTON

The US Senate voted Monday to confirm Sen. Markwayne Mullin as secretary of the Department of Homeland Security, replacing Kristi Noem.

President Donald Trump's pick was confirmed in a 54-45 vote.

In early March, Trump tapped Mullin to replace Noem, who was facing internal scrutiny following the killings of Americans Alex Pretti and Renee Nicole Good in the state of Minnesota in January by Immigration and Customs Enforcement (ICE) agents.

Democrats had been urging Trump to fire Noem, and they also signed on to an impeachment resolution against her.

During the confirmation hearing last week, Oklahoma Republican Mullin pledged to work hard to make the 280,000 DHS employees in the 22 agencies proud.

Senators pressed Mullin on incidents under Noem’s tenure.

Sen. Richard Blumenthal asked whether ICE would continue entering homes without judicial warrants.

Mullin said: “We will not enter a home or place of business without a judicial warrant unless we are pursuing an individual."

Sen. Maggie Hassan pressed Mullin on how he would differ from Noem, and questioned whether he would give the “green light to lawless behavior.”

"I will operate within the parameters and the policies and the laws that you guys set for me," Mullin responded.