NEW YORK (Reuters) - U.S. President-elect Donald Trump picked three conservative loyalists to lead his national security and law enforcement teams on Friday, underscoring his campaign promise to take a hard line confronting Islamist militancy and curbing illegal immigration.

Trump picked U.S. Senator Jeff Sessions for attorney general, rewarding a staunch supporter whose tough and sometimes inflammatory statements on immigration have reflected his own. The choice was applauded by the top Republican in the Senate but drew sharp criticism from civil rights activists.

Retired Army Lieutenant General Mike Flynn, who has championed Trump’s promises to take a more aggressive approach to terrorism, was chosen as his national security adviser.

Trump named Representative Mike Pompeo, a vocal critic of the Obama administration’s security policy, as director of the Central Intelligence Agency.

The three choices, announced by Trump’s transition team, come as the Republican president-elect works to fill key positions in his administration, which will take over from Democratic President Barack Obama on Jan. 20.

The picks could heighten concerns abroad that the Trump administration might carry out campaign promises of banning Muslims from entering the United States or imposing more severe restrictions on migrants from countries or regions with high levels of militant Islamist activity, such as Iraq and Syria.

Sessions and Pompeo seem likely to be confirmed by the Senate despite heavy resistance from Democrats. Republicans will control a majority, with at least 51 seats in the 100-seat chamber, when Congress reconvenes in January. Flynn’s post does not need Senate confirmation.

One of the earliest Republican lawmakers to support Trump’s White House candidacy, Sessions opposes any path to citizenship for illegal immigrants and was an enthusiastic backer of Trump’s campaign promise to build a wall on the border with Mexico. He has also argued for curbs on legal immigration on the grounds that it drives down wages for U.S. workers.

A former Alabama attorney general and U.S. attorney, Sessions, 69, has been in the Senate for 19 years. Allegations that he made racist remarks led the Senate to deny his confirmation as a federal judge in 1986. The chamber’s top Democrat, Chuck Schumer, said he would want Sessions to answer “tough questions” about his civil rights positions.

The attorney general acts as the country’s chief law enforcement officer and head of the Justice Department. Civil rights groups slammed Sessions as a poor choice to head a department charged with protecting voting rights and running immigration courts.

“How can we trust someone in that role who has demonstrated he thinks all forms of immigration are bad for America?” said Beth Werlin, head of the American Immigration Council.

Senate Majority Leader Mitch McConnell said he strongly supported Sessions for attorney general, calling him “principled, forthright, and hardworking.”

Sessions has been one of Trump’s most enthusiastic backers on Capitol Hill and the president-elect has hired several of Sessions’ staffers, including policy chief Stephen Miller and Rick Dearborn, who has a top job managing the transition.

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Also on Friday, the first set of transition “landing teams” were starting work at the departments of State, Justice, Defense and the National Security Council to begin hashing out the details of shifting to a new administration.

ISLAMIST MILITANTS

Flynn, one of Trump’s closest advisers, was fired from the Defense Intelligence Agency in 2014, a move he has attributed to his outspoken views about fighting Islamist militancy. Other officials who worked with Flynn cited his lack of management skills and leadership style as reasons for his firing.

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An Army intelligence veteran of three decades, Flynn was assistant director of national intelligence under Obama. He views the 2003 invasion of Iraq as a strategic blunder and has refused to condemn Trump’s support for the renewed use of waterboarding. This is an interrogation technique that simulates drowning, is widely considered torture and was banned by Obama.

Pompeo, 52, a third-term Republican congressman and former U.S. Army officer who founded an aerospace company, was a surprise pick to lead the CIA.

A member of the House Intelligence Committee, Pompeo has called for a revival and expansion of a now-defunct domestic spying programme to include “financial and lifestyle information” as well as phone records. He has said that Edward Snowden, a former government contractor who uncovered the spying programme and who now lives in Russia, should get the death penalty if he is ever tried and convicted.

Pompeo has been one of the most aggressive critics of the Obama administration’s handling of a 2012 attack on U.S. diplomatic facilities in Benghazi, Libya, that killed the U.S. ambassador and three other Americans.

Nevertheless, Democrats who have worked with him joined Republicans in describing Pompeo as knowledgeable and hard working.

“While we have had our share of strong differences - principally on the politicization of the tragedy in Benghazi - I know that he is someone who is willing to listen and engage,” Representative Adam Schiff, the top Democrat on the Intelligence Committee, said on Friday.

Trump met on Friday with former Arkansas Governor Mike Huckabee, a possible pick to head the Department of Homeland Security, and U.S. Senator Tom Cotton of Arkansas, a possible candidate for defence secretary.

Trump is considering retired General David Petraeus, who resigned as CIA chief in 2012 after an extra-marital affair, is being considered for the post of defence secretary, the Wall Street Journal said.

Trump was expected to spend the weekend in Bedminster, New Jersey, the home of the Trump National Golf Club. On Saturday he was scheduled to meet with Mitt Romney, the 2012 Republican presidential nominee.

Romney was one of the fiercest Republican critics of Trump during his unorthodox election campaign but is now under possible consideration for secretary of state.

Admiral Mike Rogers, director of the National Security Agency, is the leading candidate to serve as Trump’s director of national intelligence, the Wall Street Journal reported.