
Robert Kelly was killed by an improvised explosive device in 2004 as an infantry officer taking part in combat operations in Afghanistan

White House Chief of Staff John Kelly paid respects to his son Robert by visiting his grave at Arlington National Cemetery on Monday.

Kelly joined President Donald Trump as he delivered remarks honoring the fallen and placed a wreath at the Tomb of the Unknown Soldier at Arlington on Memorial Day.

At its conclusion, Kelly visited the grave of Robert, a marine who was killed in 2010 in Afghanistan.

His son was killed by an improvised explosive device in as an infantry officer taking part in combat operations in Afghanistan.

Kelly spent time alone at the site, and was later accompanied by his wife, Karen, who kissed their son's tombstone. Homeland Security chief Kirstjen Nielsen, Kelly's former top aide, also accompanied them.

Kelly's son's gravesite is in Section 60 at Arlington National Cemetery. Section 60 is the burial ground in the cemetery where military personnel killed in the Global War on Terror since 2001 are interred.

Last year, President Trump joined him during the visit, though this year he did not.

Kelly praised his son during a combative appearance in the White House briefing room after gold star widow Myeshia Johnson blasted Trump for how he handled the condolence call to Army Sgt. La David Johnson.

'When he died he was surrounded by the best men on this earth. His friends,' Kelly said, recalling the message he got from his condolence officer, Gen. Joseph Dunford, the chairman of the joint chiefs of staff.

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White House Chief of Staff John Kelly and his wife Karen pay their respects to their son, Marine Lt. Robert Kelly, at Arlington National Cemetery on Memorial Day, May 27, 2018 in Arlington, Virginia

Kelly spent time alone at the site, and was later accompanied by his wife, Karen Kelly (pictured kissing her son's headstone), as well as Homeland Security chief Kirstjen Nielsen, his former top aide

White House Chief of Staff John Kelly paid respects to his son Robert by visiting his grave at Arlington National Cemetery on Monday

Last year, Kelly also visited Robert's grave. He was accompanied that time by President Trump, who placed yellow flowers on the grave.

The two men have had strained relations at times, including several weeks ago when Kelly reportedly called Trump an 'idiot.' Trump called it 'fake news,' but the New York Times reported he has been venting about Kelly to friends.

Trump also reportedly tore into Nielsen in a prolonged dressing-down about illegal immigration in front of fellow cabinet members.

Kelly's son's gravesite is in Section 60 at Arlington National Cemetery. Section 60 is the burial ground in the cemetery where military personnel killed in the Global War on Terror since 2001 are interred

Kelly walks to his son's gravesite in Section 60 at Arlington National Cemetery on Monday

Secretary of Homeland Security Kirstjen Nielsen, (R) embraces Karen Kelly, wife of White House Chief of Staff John Kelly, as they pay their respects to Marine Lt. Robert Kelly

Before Kelly visited his son's headstone, Trump honored those who gave their lives while serving the nation during a speech at Arlington National Cemetery that came hours after firing off a tweet that drew criticism for focusing on his own accomplishments.

'We strive to be worthy of their sacrifice,' Trump told a crowd of servicemen and women Monday.

Trump acknowledged 'the heroes who rest in these hallowed fields, in cemeteries, battlefields and burial grounds near and far are drawn from the full tapestry of American life.'

'Theirs was a love more deep and more pure than most will ever know,' Trump said. 'They marched into hell so that America could know the blessings of peace.'

The grave of Marine Lt. Robert Kelly, son of White House Chief of Staff John Kelly, is seen at Arlington National Cemetery on Memorial Day

White House chief of staff John Kelly and his wife Karen wait for the start of a ceremony with President Donald Trump at the Memorial Amphitheater in Arlington National Cemetery on Memorial Day, Monday, May 28, 2018 in Arlington, Va.

Attending the ceremony was Sen. Bob Dole, 94, who recovered from serious injuries in World War II before his long political career, and Navy veteran Ray Chavez, who at 106 is the oldest living survivor of the attack on Pearl Harbor.

'He was in the Oval Office two days ago and he doesn't look a day over 60,' Trump said.

Then Trump singled out seven-year-old Christian Jacobs, who he met last year at Arlington while Jacobs was wearing a full Marine dress uniform in tribute to his late father, Marine Sgt. Christopher Jacobs.

'Christian walked over to me with great confidence, shook my hand, looked me straight in the eye and asked if I would like to meet his dad,' Trump told the audience, recalling the emotional visit from last year.

'Christian, I want you to know that even though your father has left this world,' Trump said, addressing his remarks to the boy in the audience. 'He's left it for the next. But he's not gone, he'll never be gone. Your dad's love, courage, and strength live in you, Christian.'

Last year: President Donald Trump speaks with Secretary of Homeland Security John Kelly and Vice President Mike Pence before laying flowers on the grave of Kelly's son, First Lieutenant Robert Kelly, at Arlington National Cemetery on May 29, 2017 in Arlington, Virginia

Paying his respects: Last year President Donald Trump also visited the grave with Kelly