Donald Trump drew laughs with a joke about giving himself the Congressional Medal of Honor as he celebrated veterans at the White House Thursday. 

The President honored service members who had each shown acts of heroism that saved lives and repelled enemy forces in Vietnam and Afghanistan.

Trump brought some humor to the event when describing the prestige of the nation's highest military honor.

'I wanted to give it to myself but I was informed I couldn't do it,' the President said with a grin.

As the crowd laughed, he added: 'And I couldn't find anything where I was actually worthy so here we are.' 

Trump bestowed the honors on Marine Corps Major James Capers Jr and Army Major Nicholas Dockery. 

He also awarded it posthumously to Marine Corps Colonel John W Ripley, who died in 2008.

'These are great men, great people,' Trump said at the ceremony. 'We thank you and we will never, ever forget you.'

Capers, 88, was honored for risking his life to ensure the safety of his fellow Marines after they were ambushed in Vietnam in 1967. 

A reconnaissance mission to find a suspected North Vietnamese base camp turned into days of bloody fighting in dense jungle, according to his citation.

On the fourth day, his team was ambushed and outnumbered by Vietnamese fighters. A mine explosion left Capers with a broken leg and serious wounds to his abdomen.

'After a shot of morphine, Jim asserted command of the firefight,' Trump said, drawing on accounts of the mission. 'He took over like nobody's ever seen before.'

Capers called in air support to repel the ambush. When a rescue helicopter arrived, Capers loaded all the wounded men before climbing aboard.

Trump shared a moving moment with him as he pinned the Medal of Honor around Capers' neck, clasping Capers by the shoulders and pulling him forward to make sure the medal was straight and level against his chest. 

Capers had been keeping a straight face but broke into a smile when Trump grinned.

Ripley was honored for a heroic effort to halt the advance of North Vietnamese forces by blowing up a crucial bridge in 1972.

A force of more than 30,000 North Vietnamese soldiers and 200 tanks was approaching the bridge in the village of Dong Ha when Ripley single-handedly placed 500 pounds of explosives to bring it down, according to his citation.

Over the course of five hours, Ripley climbed back and forth along the bridge's steel beams, exposing himself to enemy fire as he placed the charges.

'John completed not one, not two, but five such trips,' Trump said, calling him a 'very strong guy.'

Ripley said a prayer, then detonated the bridge, sending it into the water below and halting the North Vietnamese advance, Trump said.

Ripley died in 2008. His three sons and other family members attended the ceremony.

Dockery's platoon members were guarding a compound in Afghanistan's Kapisa Province in 2012 when they were ambushed by an estimated 150 Taliban fighters. 

He raced across open ground to rally his scattered team then set out to find missing soldiers, according to his citation.

After carrying a wounded soldier away from gunfire, he spotted two enemy fighters heading toward another wounded soldier in an alley. 

Dockery killed the two fighters before performing CPR on the American soldier to get him breathing again, his citation said. 

He called in mortar support, then shielded the wounded soldier from the blasts with his own body.

After hours of fighting in the close urban setting, Dockery used smoke grenades to signal enemy positions for American gunships.

 He refused to leave the village until all the wounded soldiers were taken to safety.

'You were the last man to depart the battlefield that day,' Trump told him, 'and you left it a legend and a hero.'