An overflow crowd has attended a memorial service at a church in the Quebec town of Lac-Megantic for the 47 people who were killed there when a runaway oil train derailed and exploded.

About 1,000 people packed Sainte-Agnes church for the Saturday morning Mass presided over by Luc Cyr, the archbishop of Sherbrooke.

Among the dignitaries attending were Canadian Prime Minister Stephen Harper, Quebec Premier Pauline Marois and the town's mayor, Colette Roy-Laroche.

Parish priest Steve Lemay said what happened to residents' beloved town was an unheard of tragedy that has brought incomprehensible suffering to its people.

Forty-two people were killed died on July 6 when a runaway train carrying crude oil careened off the tracks and exploded into a fireball, devastating the lakeside town of 6,000. Five others are still missing.

Al Jazeera’s Cath Turner, reporting from Lac-Megantic, said that there were thousands of people inside the church. Most were relatives of the 46 people killed in the accident.

The rest of the town was out in the street watching the service on a large television screen.

“It is impossible in this town to find someone who does not know someone killed in the accident or affected by the train accident” she said.

The exact cause of the crash is still not known and the site is still considered as crime scene by police who are gathering evidence and searching for five people who are still missing, our correspondent added.

Source: Al Jazeera and agencies