Hundreds of mourners are taking part in a march to commemorate the victims of France's deadliest road accident in more than 30 years.

Prior to the march, family members of the 43 people who died in Friday's fiery crash between a truck and a bus full of retirees gathered Sunday for a church ceremony in Petit-Palais-et-Cornemps — a village in southwestern France where many of the victims lived.

In an emotional ceremony, local official Harry Sabarot said the community had been "overwhelmed" by the tragedy but the dramatic accident "won't be forgotten."

President Francois Hollande will attend an official commemoration ceremony for the victims Tuesday in Paris.

An investigation has begun but police have not yet identified the cause of the crash.