NEW YORK/WASHINGTON (Reuters) – President-elect Donald Trump plans to nominate a third retired general for a top job in his new administration with the choice of a battle-hardened Marine commander to lead the agency set up after the Sept. 11, 2001 attacks to protect the U.S. homeland.

Trump is expected to name former Marine General John Kelly, 66, as head of the Department of Homeland Security, a source familiar with the situation told Reuters on Wednesday.

In confirmed by the Senate, Kelly will be in charge of the agency tasked with securing borders against illegal immigration, protecting the president, responding to natural disasters, coordinating intelligence and countering terror threats.

Like Trump, Kelly is believed to hold strong views on stopping illegal immigration. The four-star general told a congressional committee last year that the lack of security on the U.S.-Mexican border represents a national security threat.

The former head of the military’s Southern Command, Kelly was responsible for U.S. military activities and relationships in Latin America and the Caribbean. He was a proponent of keeping open the U.S. military prison in Guantanamo Bay, Cuba.

Kelly, whose son was killed fighting the Taliban in Afghanistan, retired in January after a 45-year military career. CBS first reported that Trump would nominate Kelly to the position, which would put him in charge of more than 240,000 employees. Those include Secret Service and Border Patrol agents as well as the agency that clears refugees for resettlement in the United States.

Trump energized voters in the election campaign by promising to build a wall on the U.S.-Mexico border in order to keep out Mexican immigrants he described as rapists and murderers.

In 2015 testimony before the Senate Armed Services Committee, Kelly said people-smuggling activities on the southern border were a dire threat.

“Terrorist organizations could seek to leverage those same smuggling routes to move operatives with intent to cause grave harm to our citizens or even bring weapons of mass destruction into the United States,” Kelly said.

Such sentiments may have endeared him to Trump, who warned repeatedly during his presidential campaign of dangers from illegal immigration, and pledged to build a wall along the border and make Mexico pay for it.

The Republican president-elect, who has no military experience, also plans to nominate retired General James Mattis to lead the Pentagon and picked retired Lieutenant General Michael Flynn to be his national security adviser.

MILITARY EXPERIENCE

Kelly served in Iraq several times, and in 2003 was the first Marine in more than 50 years to be promoted to the rank of brigadier general while in a combat zone.

In November 2010, his son, Marine 1st Lieutenant Robert M. Kelly, was killed in Helmand Province in southern Afghanistan.

According to a report in the Los Angeles Times, at the younger Kelly’s burial ceremony at Arlington National Cemetery outside Washington, his father said he preferred not eulogize his son.

Rather, Kelly said, he wanted to honor all those who enlisted after the Sept. 11 attacks, ready to fight “an enemy that is as savage as any that ever walked the earth.”

Although Kelly’s military experience may give him insight into overseas threats like drug trafficking or Islamist militancy, he would face new challenges at an agency that oversees everything from airport security to protecting against cyber threats and responding to domestic security crises.

Kelly also questioned the Pentagon’s decision to allow women to serve in combat, and differed publicly with President Barack Obama over the Democrat’s attempt to close the Guantanamo Bay prison.

“There are no innocent men down there,” Kelly said of Guantanamo in a January interview with the Military Times newspaper.

The Republican-controlled Senate must confirm Kelly for the Homeland Security post. He would be the fifth secretary of the United States’ newest cabinet-level agency and the first to serve without a background in law.

(Reporting by Steve Holland and Warren Strobel; Writing by Julia Edwards Ainsley; Editing by Jonathan Oatis and Alistair Bell)

IMAGE: U.S. President-elect Donald Trump appears with retired Marine Corps General John Kelly outside the main clubhouse after their meeting at Trump National Golf Club in Bedminster, New Jersey, U.S., November 20, 2016. REUTERS/Mike Segar/File Photo