Attorney General Jeff Sessions recalled his childhood in segregated Alabama as he invoked the memory of Martin Luther King Jr. on Tuesday and called on Justice Department employees to "remember, celebrate and act."

"I regularly saw raw, unvarnished discrimination against a whole people because of the color of their skin," Sessions said at a commemorative program for the late civil rights leader. " . . . I can remember riding on an all-white school bus and passing every morning an all-black school bus. Just one look at the buses was enough to know that separate was not equal."

Sessions praised King, who he said "helped transform our legal system by inspiring some of the transformative laws that we in this building enforce today," referencing the Civil Rights Act of 1964, the Voting Rights Act of 1965 and the Fair Housing Act of 1968.

"All he had were his words and the power of truth," Sessions said. " . . . His message, his life and his death changed hearts and minds. Those changed souls then changed the laws of this land."

But civil rights leaders criticized Sessions's remarks, made at a time, they said, when the Justice Department is rolling back efforts to promote civil and voting rights.

"It is beyond ironic for Jeff Sessions to celebrate the architecture of civil rights protections inspired by Dr. King and other leaders as he works to tear down these very protections," said Vanita Gupta, the head of the Justice Department's civil rights division under President Barack Obama and now president of the Leadership Conference on Civil and Human Rights.

"Make no mistake," Gupta said. "If Dr. King were alive today, he would be protesting outside of Jeff Sessions's office."

Kristen Clarke, president and executive director of the Lawyers' Committee for Civil Rights Under Law, said that in the past year, the Justice Department under Sessions has taken action to "obstruct and reverse civil rights enforcement."

She and others point to a new policy that calls for federal prosecutors to pursue the most serious charges even if that might mean minority defendants face stiff, mandatory-minimum penalties. Sessions has defended President Trump's travel ban and threatened to take away funding from cities with policies he considers too lenient toward undocumented immigrants. The department's new guidance and stances on voting rights and LGBT issues also might disenfranchise minorities and poor people, civil rights advocates say.

Justice officials say that Sessions's actions reflect an aggressive, by-the-book interpretation of federal law and that his policies are geared toward fighting violent crime and drug trafficking.

Sessions was joined Tuesday by Deputy Attorney General Rod J. Rosenstein and Larry D. Thompson, who served as deputy attorney general under President George W. Bush.

Trump's nominee to head the civil rights division, Eric Dreiband, has not yet been confirmed by the Senate. In his place, John M. Gore, acting as the assistant attorney general for the division, was on stage.

"Every day, we at the civil rights division are honored to carry on this fundamental work of our democracy and enforce the nation's civil rights laws, including the civil rights laws that Dr. King fought for," Gore said. "We work zealously to combat hate crimes, to end the scourge of human trafficking, and to guarantee equal rights and equal access for all Americans at the ballot box, in housing, in education, in employment and public accommodations, and in criminal justice."