A 4-year-old boy critically injured when his grandfather lost control of their car, striking a tree in Bethpage on Monday, has died, Nassau County police said Wednesday.

At the request of the family, police have not released the name of the child or his 65-year-old grandfather.

Police said the boy died at the Cohen Children’s Medical Center in New Hyde Park.

The child was buckled into a car safety seat when the 2008 Nissan Altima driven by his grandfather went out of control on northbound Stewart Avenue near Arthur Avenue at 1:20 p.m., police said.

advertisement | advertise on newsday

The car careened over the sidewalk, police said, striking the tree.

The grandfather also was injured, but his injuries were not life-threatening, police said.