Prime Minister Stephen Harper drew a direct line from Sunday's losses in Afghanistan to the sacrifices in the Battle of Vimy Ridge 90 years ago.

"Sadly, today has been a difficult day in Afghanistan," Harper told a group of veterans minutes after learning of the deaths of six Canadian soldiers.

"Our hearts ache for them and their families. And I know as we gather here on Easter Sunday, our thoughts and prayers are with them.

"Today's events once more remind us of the sacrifices that our men and women in uniform continue to make against those who threaten freedom, democracy and human rights."

Harper is in France for the 90th anniversary commemoration of the Battle of Vimy Ridge in the First World War.

The prime minister, his wife Laureen and their two children went to church in Vimy, France on Easter Sunday -- one that has a stained glass window commemorating the valour of Canadian soldiers.

They then toured the historic battleground where Canada played a key role. France gave the pristine 100-hectare memorial park to Canada in 1922.

The family then travelled to Arras, a community about 15 kilometres from the memorial for the Freedom of the City ceremony. Arras is giving Canada a symbolic key to the city in a gesture of friendship.

Harper made an address during the visit, saying the Battle of Vimy Ridge forged a bond between the two nations that lives on today. He spoke about 400 years of history and enduring friendship between Canada and France, addressing a crowd of several thousand as part of a ceremony in the town square.

"The Freedom of the City ceremony is steeped in the noblest military traditions. Today, we celebrate the trust and friendship between two nations and our citizens," Harper said.

"Of all the ties that bind Canada and France, few are stronger than those forged right here, nine decades ago, during the Battles of Arras and Vimy Ridge."

The ceremony included a tribute to Canadian servicemen with a parade led by the Canadian Forces.  The Canadian troops marched through the community up to City Hall, where Mayor Jean-Marie Vanlerenberghe presented the Canadians with the Freedom of the City scroll, in honour of the Canadian conribution during the war.

Vanlerenberghe returned Harper's warm sentiments and in addition to handing over the key he also presented him with an eight metre-tall symbolic door, for the prime minister to take home to Canada.

The Harpers landed in northern France on Saturday after leaving Ottawa on a Canadian Forces jet that morning.

This is the first official overseas trip for Ben and Rachel.

For Ben, there's a special connection. His mother's great grandfather -- Benjamin Teskey, Ben's namesake -- was at the original Vimy Memorial dedication in 1936.

A crowd of about 25,000 people is expected to attend the official ceremony on Monday, when Queen Elizabeth will officially dedicate the refurbished Vimy monument.

With a report from CTV's David Akin and files from The Canadian Press