America’s new top prosecutor, Jeff Sessions, has said the US must bring an end to illegal immigration, as he was sworn in at the White House.
The US attorney general said: “We need to end this lawlessness that threatens the public safety, pulls down the wages of working Americans.”
President Donald Trump said the former Alabama senator would be “a great protector of the people”.
The Senate confirmed him in the post on Wednesday by a vote of 52 to 47.
He was appointed after a series of divisive congressional hearings over his record on civil rights.
Vice-President Mike Pence administered the oath in the Oval Office.
“We need a lawful system of immigration,” Mr Sessions said after he was sworn in.
“One that services the interest of the people of the United States. That’s not wrong, that’s not immoral, that’s not indecent.”
Mr Sessions also pledged to address the country’s crime problem, which he called a “dangerous and permanent trend that places the health and safety of the American people at risk”.
The Alabama lawmaker, whose nomination was among Mr Trump’s most controversial, resigned his Senate seat shortly after his colleagues confirmed him.
At 70, Mr Sessions is the same age as Mr Trump and was one of the earliest supporters of the president.
He will now take charge of the justice department and its 113,000 employees, including 93 US attorneys.
Allegations of racism have dogged Mr Sessions since he was rejected by the Senate in his nomination for a federal judgeship in 1986.
That nomination was rejected by a US Senate panel amid concerns over allegedly racist comments made by Mr Sessions.
Senate Democrats highlighted these allegations in debates ahead of the vote.
Elizabeth Warren was silenced ahead of his confirmation vote after she recalled criticism of Mr Sessions by Martin Luther King’s widow, who alleged he had intimidated black voters.
Ms Warren, who was temporarily banned from the chamber, wrote: “If Jeff Sessions makes even the tiniest attempt to bring his racism, sexism & bigotry into the Justice Department, he’ll hear from all of us.”