An eight-year-old Kingston boy and his grandfather have drowned after a failed rescue attempt on Lake Ontario.

The tragedy happened shortly after the child started to struggle in the water near the shore of Patterson Park, west of downtown Kingston on Monday.

Several witnesses joined the boy's family to try to rescue the child by forming a human chain. The rescue attempt, however, turned to tragedy when the child's 67-year-old grandfather lost his grip and was pulled under water.

Police say Monday's high winds made the lake's swimming conditions treacherous.