NEGOMBO, Sri Lanka — The coffins came one by one, some heavy and others unusually light.

As bulldozers tore into the fresh earth, clearing an enormous burial ground, barefoot men dripping with sweat scooped shovelfuls of dirt. The sun beat down, and one family stood in the shade. They were here for the burial of an 11-year-old boy.

“I don’t even know what to say,” said Lasanthi Anusha, whose son stood looking at the grave of his friend. “There were even smaller ones.”

Mass burials of the victims of Sunday’s suicide attacks in Sri Lanka, which killed more than 350 people, including dozens of children, began on Tuesday.

The bombers, identified as Islamist extremists by the government, struck three churches during Easter Mass and three hotels. In Negombo, the site of the deadliest attack, armored personnel carriers lined the roads as funeral rites unfolded amid intense security and sadness.