Ottawa police have launched an investigation after the publication of photographs of young men urinating on the National War Memorial during Canada Day celebrations.

The suspects can be charged with mischief for urinating in public.

Dr. Michael Pilon, a retired major with the Royal Canadian Dental Corps, snapped photos of several men defacing the Ottawa monument after the holiday fireworks on Saturday night.

The Tomb of the Unknown Soldier, built in front of the National War Memorial, holds the remains of an unidentified Canadian soldier who died in the First World War and represents the more than 116,000 Canadians who died in past conflicts.

Pilon, who served with the Royal Canadian Dental Corps, said most of the crowd reacted with cheers and laughter.

He said that while he is disappointed by what he witnessed, he has seen it before.

"Last year this sort of thing was going on. People were actually sitting on the tomb," he told CTV's Canada AM on Tuesday.

He sent emails to the offices of Premier Dalton McGuinty, Mayor Bob Chiarelli, the National Capital Commission and others, asking for someone to guard the memorial this year.

But he received no response to his request, he said.

"That's the insult -- more so than those kids that were allowed to get up there," he said.

Prime Minister Stephen Harper told an Ottawa radio station on Monday that the vandals' actions don't reflect the views of the rest of the nation.

"As you know often, people who get carried away do thoughtless things," Harper said. "Obviously, it's a terrible thing to do."

"Certainly my impression is it doesn't represent in any way the views of any segment of Canadian society," he said. "I think we all strongly honour our vets."

The National War Memorial, unveiled in 1939, initially symbolized the response of Canadians in the First World War but has since come to commemorate the sacrifice of all Canadians who have served in times of war.

The Royal Canadian Legion plans to use the photos to pressure the government for increased security at the monument.

H. Clifford Chadderton, chairman of the National Council of Veteran Associations in Canada (NCVA), told CTV.ca that veterans' groups have been asking for more security since 1995 but especially since the creation of the Tomb of the Unknown Soldier in May 2000.

"It (the incident) indicates that the government has got to do more than bring a soldier home from overseas and put him in the Tomb of the Unknown Soldier and then forget about him," Chadderton said.