Jeff Sessions was sworn in as America's top law enforcement officer on Thursday, promising to back up President Donald Trump's actions on immigration and crime with renewed energy from the Department of Justice.

Sessions, a former U.S. senator from Alabama, cited 'the threat of terrorism' and said rising crime rates are ' a dangerous permanent trend that places the health and safety of the American people at risk.' He also defended Trump's contention that unchecked immigration is a threat that requires action.

'You've said something that I believe and I think the American people believe,' Sessions said to the president, 'that we need a lawful system of immigration, one that serves the interests of the people of the United States.'

'That's not wrong, that's not immoral, that's not indecent,' he said.

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President Donald Trump watched Thursday as Vice President Mike Pence administered the oath of office to Attorney General Jeff Sessions

Sessions, who resigned his U.S. Senate seat to take the top Justice Department job, defended Trump's views on immigration, crime and terrorism

Sessions resigned his Senate seat shortly after his colleagues approved him on a 52-47 vote that broke largely along partisan lines.

He was the first member of the Senate to endorse Trump when he ran for president.

Sessions also contributed to the Trump campaign's policy shop, sending top aide Stephen Miller to work for the billionaire political upstart.

Miller, 31, is now in charge of the White House's domestic policy development.

The Sessions confirmation, followed by Thursday's swearing-in by Vice President Mike Pence, was marred by an all-night debate staged by Democrats as a stalling tactic, putting off a final vote for 30 hours.

Ultimately one Democrat, Joe Manchin from the deep-red state of West Virginia, joined the Republicans in voting for him. Sessions himself abstained from casting a ballot on his own nomination, recording his vote as 'present.'

Sessions, widely seen as an inspiration for Trump's anti-immigration policies, is just the sixth of 15 cabinet members to be confirmed, in addition to the cabinet-rank positions of CIA director and U.S. ambassador to the United Nations.

Sessions takes charge of the Justice Department and its 113,000 employees, including the 93 U.S. attorneys throughout the country.

He steps in amid a swirling legal debate over Trump's most controversial White House action to date, an executive order temporarily blocking all refugee arrivals and immigration from seven mainly Muslim countries.

Sessions was the sixth of 15 cabinet members to be confirmed, in addition to the cabinet-rank positions of CIA director and U.S. ambassador to the United Nations

The genteel Sessions, who like the president is 70 years old, was a U.S. attorney for the southern district of Alabama from 1981 to 1993, before serving two years as the state's attorney general. He won a Senate seat in 1996.

But his career was almost derailed in 1986 when a Senate panel rejected his nomination for a federal judgeship amid concerns over past comments he made about blacks, and over remarks that Democrats called sympathetic to the Ku Klux Klan.

The late Pennsylvania Democratic Senator Arlen Specter said before he died that his vote against Sessions that year was one he regretted.

Trump used Thursday's photo-op with Sessions to sign three executive orders aimed at combating drug cartels and violent crime, including attacks on police officers.