President-elect Donald Trump, in filling the first of many top positions in his administration, has chosen three staunchly conservative Republicans to fill vital roles: Senator Jeff Sessions as his attorney general, Congressman Mike Pompeo as director of the Central Intelligence Agency, and retired Lieutenant General Mike Flynn as his national security adviser.
All three candidates, who have been loyal to Trump throughout his unconventional campaign, are hard-liners who will head up his national security and law enforcement teams.
Sessions strongly backed and advised Trump since the beginning of his presidential campaign.
Pompeo, from the Midwestern state of Kansas, was among the first group of conservative tea party congressional members to be elected in 2010.
Flynn, a decorated combat veteran, served as Trump's go-to national security adviser during the campaign. Flynn's selection would not require U.S. Senate confirmation, unlike those of Sessions and Pompeo.
Sessions could face tough questions during hearings, even with Republicans in control of the chamber. When Sessions was nominated for a federal judicial position 30 years ago, he was sharply criticized for racist remarks he allegedly made while serving as U.S. attorney in his home state of Alabama.
During the 1986 Senate hearing, former assistant U.S. attorney Thomas Figures, an African-American, testified that Sessions referred to him as "boy" and warned Figures to be careful about what he said to "white folks."
Sessions denied he ever called Figures "boy," but the late U.S. Senator Edward Kennedy produced a letter from a group of African-American attorneys that said Figures made the allegations about Sessions to the group at least twice.
Former colleagues also testified that Sessions joked that the Ku Klux Klan, a white extremist group, was "OK until he learned they smoked marijuana."
Sessions eventually withdrew from consideration for the judicial post and went on to become state attorney general before winning election to the Senate in 1996.
Sessions is also known for his anti-immigration position. He has opposed most immigration bills the Senate has considered over the past two decades, including those supporting legal immigration. And a Sessions aide helped the president-elect articulate his immigration policy.
If Sessions is confirmed as attorney general by the Senate, he would be the country's top prosecutor and law enforcement official.
FILE - House Benghazi Committee member Rep. Mike Pompeo, R-Kan., questions Democratic presidential candidate Hillary Clinton, during the committee's hearing on Capitol Hill in Washington.
In a statement, Trump said Pompeo will be a "brilliant and unrelenting leader" of the CIA.
After graduating first in his class at West Point in 1986, the 52-year-old congressman served as a U.S. Army Calvary officer.
Pompeo is a member of the House Permanent Select Committee on Intelligence and founded and subsequently sold Thayer Aerospace, which makes components for commercial and military aircraft.
A close ally of Vice President-elect Mike Pence, Pompeo is a staunch opponent of President Barack Obama's nuclear agreement with Iran.
Pompeo "is a serious guy who studies issues carefully," former National Security Agency and CIA director Michael Hayden told Reuters on Friday.
Retired Lieutenant General Michael Flynn, seen in this 2014 file photo, will join Drone Aviation Holding Corp as vice chairman of its board of directors. Flynn has been advising Republican front-runner Donald Trump informally on foreign policy.
National security adviser
Flynn will most likely play a big role in Trump's foreign policy decisions moving forward, because Trump has no practical military experience.
The 57-year-old Democrat is a decorated combat veteran who retired as a three-star general, one of the highest ranks possible. He is also the former head of the Defense Intelligence Agency.
After several years of successive promotions within Army intelligence operations, Flynn was nominated by U.S. President Barack Obama to be director of the Defense Intelligence Agency. He held the position for two years before retiring in 2014 after reportedly being forced out for his poor management style.
Flynn was criticized by former colleagues last year when he traveled to Moscow and appeared next to Russian President Vladimir Putin at a posh event for the state-run propaganda television channel Russia Today (RT). Flynn said he was paid to attend the event and defended the trip by saying he believed RT was no different than some American all-news channels.
WATCH: Vice President-elect Mike Pence on Trump's new hires
Meanwhile, Trump and his transition team traveled about 75 kilometers (47 miles) Friday from Trump Tower to the Trump National Golf Club in Bedminster, New Jersey.
They planned to work through the weekend to fill other key positions in the administration.
Also Friday, New York City Mayor Bill de Blasio said the increased security and police presence around Trump Tower in midtown Manhattan would continue until Trump's inauguration on January 20. The city said it was considering asking for federal help to cover the increased costs.
"We're being asked to do something on a scale that's never been done before," de Blasio said at a news conference with New York Police Department and Secret Service officials.
The mayor said security would be reassessed after the inauguration, if Trump decided to split time between the White House and Trump Tower.