A memorial for the victims of the Air India tragedy, inscribed with the names of all the 331 people who lost their lives in the bombing, was unveiled in Toronto on Saturday as Canada [Images] observed its 22nd anniversary.

Opening the memorial -- featuring a sundial, gardens and a granite wall, Prime Minister Stephen Harper said his government is serious about the threat of terrorism, as evidenced by its decision to launch a probe into the tragedy.

"We must act to ensure such an atrocity is never again visited upon our fellow citizens," Harper said on the shore of Lake Ontario.

The memorial is inscribed with the names of the 329 people who were aboard the Flight 182 when it blew up off the coast of Ireland on June 23, 1985, and the names of the two baggage handlers who were killed in a related explosion at the Narita airport in Tokyo the same day.

"The sundial is supported by a wall that is made in part from stones from all of the provinces and territories in Canada. There are also stones there from India, US, Ireland and Japan [Images]. All of these countries were directly affected by the tragedy," Peter Klambauer, who co-coordinated the project for the city of Toronto, said.

Families of the victims said the memorial gives them a tangible place to grieve the loved ones they lost.

About two-thirds of the relatives of Air India bombing victims live in Toronto.

Susheel Gupta, who is now a federal Crown prosecutor in Ottawa but was just 12 when his mother Ramwati Gupta died on the Kanishka flight, said the memorial has been a long time coming.

"I think it's been a long 22 years that we've waited for something like this. It's certainly a symbolic gesture but I hope the memorial serves as a reminder to all Canadians to remember that terrorism is a real threat in this country," said Gupta.

Speaking on the occasion, Toronto Mayor David Miller said, "By building this memorial we are saying that in this city there is no room for violence, there is no room for injustice, there is no room for hate."

Ontario Premier Dalton McGuinty said the gathering underscored the importance of taking time to remember the victims of terror, and that he hoped the memorial would help bring a sense of peace to the families of the victims.

A reception was held in Toronto last night for the family members to meet the hundreds of people who were involved with the design and construction of the memorial.

Only one man -- Inderjit Singh Reyat -- has ever been convicted in the attacks. He was sentenced to five years in prison in 2003 after striking a plea bargain under which he was convicted on lesser charges of manslaughter and with assisting in the construction of the bomb.  

A public inquiry into the disaster, led by former Supreme Court justice John Major, will resume its work in the fall after taking a break for the summer.