In a touching moment on Monday, Donald Trump embraced a wounded and wheel-chair bound veteran from Afghanistan who sang 'God Bless America' at a ceremony to honor the new incoming chairman of the Joint Chiefs of Staff.

The rare display of affection from the president came after U.S. Army Captain Luis Avila sang the patriotic hymn in a ceremony filled with a 21-gun salute, a fife and drum corp, military bands, and other pomp and circumstance.

It was an emotional moment for those present, which included Vice President Mike Pence, Defense Secretary Mark Esper, incoming Chairman of the Joint Chiefs of Staff Gen. Mark Milley and former Chairman of the Joint Chiefs of Staff Joseph Dunford.

Donald Trump embraced a wounded and wheel-chair bound veteran from Afghanistan who sang 'God Bless America'

U.S. Army Captain Luis Avila sang the patriotic hymn at a ceremony to honor the new incoming chairman of the Joint Chiefs of Staff

In December 2011, Avila was leading a search and rescue mission along the Afghanistan-Pakistan border when a 600-pound improvised explosive device detonated underneath his vehicle - wounding him severely and killing three others.

Avila suffered two strokes and two heart attacks, along with a severe lack of oxygen which caused anoxic brain damage - injuries that left him almost completely paralyzed and confined to a wheelchair. His left leg was also amputated, according to the Department of Veterans Affairs.

He spent 40 days in a coma before he woke up.

He has used music therapy in his recovery and was the featured singer for the ceremony honoring Milley's appointment and Dunford's retirement after more than four decades in the Marine Corps.

Milley joined Trump and the others to listen to Avila sing near the conclusion of the ceremony, which happened on a rainy day at Fort Myer in Northern Virginia.

During the song Trump bobbed his head along with the music and gave Avila his signature thumbs up sign. When Avila finished his solo, the president and other guests of honor joined in singing another verse.

And, when the song was done, Trump walked over to Avila, arms held out wide, to give a big bear hug to him and his wife Claudia, who appeared to be holding back tears.

The rest of his national security team also offered hugs to Avila, who appeared to give them, including the president, a challenge coin.

Army Captain Luis Avila sings God Bless America for Chairman of the Joint Chiefs of Staff Army General Mark Milley, Vice President Mike Pence, President Donald Trump, Secretary of Defense Mark Esper and others

Trump gave a big bear hug to Captain Avila and his wife Claudia

Family: Capt Luis Avila and his wife Claudia now live in Maryland, close to Washington D.C., in a house specially adapted for his wounds

Service: Aliva served five combat tours of Iraq and Afghanistan, becoming an officer in 2004 after four years in the ranks

Duty: Captain Avila was on his fifth tour and leading the leading the 720th Military Police Battalion when he was wounded by an IED

Long road to recovery: Capt Avila spent 40 days in a coma and suffered two heart attacks and a stroke as his wife prayed for him to survive. He was hailed by Donald Trump on Monday - and also by President Obama in 2014

Devotion: Capt Aliva and his wife Claudia now have three sons - Luis Jr., Miguel and José

Dunford paid tribute to Avila and all wounded veterans earlier in the ceremony.

'At the end of this ceremony, you will hear Army Captain Luis Avila sing a tribute to America.

'Captain Avila was seriously wounded in action and today, represents all of the wounded warriors and killed in action of our military.

'Both our friends and enemies alike should know that we who wear the uniform of the United States of America, the cloth of our nation, we are all Captain Avilas,' Dunford said.

Avila also performed 'God Bless America' during the 2017 National Memorial Day Concert with soprano Renée Fleming.

And in 2014, Barack Obama hailed the captain and his wife at a special concert in the White House honoring troops, singling out the Alivas as a family he had come to know and saying they were 'representative of what it means to serve the United States of America, to be a true patriot.'