SCHENECTADY — Six children and their mother were injured Wednesday evening when they were hit by a truck while crossing State Street.

Police department spokesman Officer Kevin Green said the mother and her children were crossing near Chestnut Street just after 6 p.m. when they were struck by a Chevrolet 1500 pickup truck that was heading downtown.

The children were as young as 2 years old, but police did not know all of their ages. Scanner traffic reported one as 6 years old and another as 11. Green said two of the younger children were airlifted to Albany Medical Center Hospital, where they remained in critical condition late Wednesday.

The four other children were transported by ambulance to Ellis Hospital. Their injuries were not believed to be life-threatening.

The mother was also taken to Albany Medical Center Hospital with the more seriously injured children.

Police had not released the names of the victims or the driver late Wednesday.

The Daily Gazette’s news-gathering partner, CBS 6, reported that police questioned the driver of the truck and he was released. A witness also told CBS 6 that the mother was pushing her children in a shopping cart with the youngest in a stroller when the accident happened.

Police blocked off State Street from Hulett Street to Catherine Street as Mohawk Ambulance and Schenectady Fire Department personnel tended to the injured. A purple stroller, two pairs of sneakers and a shopping cart lay in the street.

Crime scene investigators worked late Wednesday to reconstruct the accident. They took measurements, made chalk markings on the pavement to indicate locations and marked evidence in the street with numbered tags. Twenty distinct tags could be seen.

The accident is still under investigation, Green said: “I don’t know how it happened.”