As Canadians mark the 100th anniversary of the Armenian genocide Friday, one former Liberal MP is reflecting on his years-long fight to have Ottawa officially recognize the slaughter.

Sarkis Assadourian remembers when MPs passed a resolution in 2004 officially recognizing the 1915 massacre as genocide and condemning it as a crime against humanity.

It was April 25, and the resolution overwhelmingly passed, 153 to 68.

As MPs stood to cheer and applaud on the floor of the House of Commons, Assadourian broke down in tears. For him, the recognition was deeply personal, as it marked the end of a hard-fought slog.

"It was an 11-year fight for me," he told CTV's Canada AM. "I had made four, five attempts to pass the general resolution – they all failed."

Ottawa had resisted past attempts to recognize the massacre as genocide for various political reasons, including its relationship with NATO ally Turkey.

But on that day, Assadourian, who is the son of survivors of the Armenian genocide, went the extra length to see that the vote would pass.

He printed up letters asking MPs who did not want to vote for the motion to instead abstain.

"On that day, I passed out 308 letters to each and every member of Parliament, asking them to please vote for it, (and) if you can't vote for it, abstain," he said.

Recognizing the Armenian genocide continues to be a contentious issue. Only 24 countries currently recognize the genocide, with Germany and Austria being the latest nations to join the ranks this week.

The turn by both Germany and Austria is particularly significant as both countries were allied with the Ottoman Empire when the atrocities took place during the First World War.

Despite promising to do so while he was a senator, U.S. President Barack Obama has still not used the word "genocide" to describe the massacre.

Recognition not enough

But simply recognizing the genocide happened is not enough, says Canadian-Armenian filmmaker Atom Egoyan.

Egoyan, whose 2002 film "Ararat" explored the challenges of depicting the genocide in art, said it's critical that Turkey recognize its role in the slaughter.

Historians estimate that up to 1.5 million Armenians were killed by Ottoman Turks over the course of the massacre that started in 1915.

"It's really important to remember that we're not only commemorating 100 years since the genocide itself, but it's been 100 years of denial by the perpetrator," Egoyan said.

Turkey has been vociferous in its denial that the mass killing was genocide. When Canada recognized it in 2004, Turkey temporarily withdrew its ambassador in response.

And again, this week, Turkey said it was recalling its ambassador from Austria, after that country recognized the genocide.

Egoyan said until Turkey can recognize the crimes of the past and have an open dialogue on the killings, those affected by the 1915 slaughter can never truly heal.

"This is really an appalling condition, because it keeps the wound open," he said.