Four Canadian soldiers killed by American friendly fire in Afghanistan three years ago were honoured at a special tribute in the United States on Monday.

The soldiers were remembered in a ceremony at Fort Campbell, Kentucky, where their names were added to a wall honouring Americans who died in combat -- marking the first time that names of non-U.S. soldiers were added to the memorial wall.

On Monday, Col. Michael Steele paid tribute to the memory of the Canadians and three American soldiers who died in Iraq.

"Freedom is not free," he told the crowd. "Anyone who fights with us is a brother," said Steele. "We come here to remember, not so much to grieve for the fallen, but rather to lift them up."

Cpl. Ainsworth Dyer, Sgt. Marc Leger, Pte. Richard Green and Pte. Nathan Smith were all killed when a U.S. fighter pilot, Maj. Harry Schmidt, dropped a 225-kilogram bomb on them on April 18, 2002.

The Canadian soldiers were conducting a nighttime military exercise near Kandahar when the bomb was dropped.

Schmidt, an Illinois National Guard pilot, said he mistook the gunfire for an attack from Taliban fighters and said his superiors never told him they would be conducting exercises that night.

In addition to the four who died in the blast, eight others were injured. All were members of the Edmonton-based Princess Patricia's Canadian Light Infantry.

Monday's event, held on the base of the 101st Airborne, included 180 regiment soldiers dressed in fatigues and berets. They were joined by 14 members of the Princess Pats.

The tribute to the fallen soldiers left shaken family members in tears.

"Marc fought with his brothers and now he's with his brothers,'' said a shaken Richard Leger, father of Sgt. Marc Leger. "It means an awful lot to me to understand that.''

Meanwhile, Pte. Smith's father Lloyd said the tribute was "not a political gesture."

"This is coming from the men on the ground. This is coming from the heart. It's very important for our sons to be recognized by the rank and file."

Last year, Schmidt was found guilty on four counts of dereliction of duty, for which he was grounded, reprimanded and docked one month's salary.

Charges against the flight leader, Maj. William Umbach, were dropped and he was permitted to retire from the Air National Guard.

The Legers have framed a copy of Schmidt's reprimand and have it hanging over their fireplace.

"There is no such thing as closure for us," Richard Leger said. "Remembrance Day is always going to be there for us."

Also honoured at the ceremony were Cpl. Pierre Piche, Specialist John Sullivan and Sgt. Ariel Rico, who died in Iraq in November 2003.

With files from The Canadian Press