PITTSBURG -- A 4-year-old boy remained hospitalized Wednesday after being hit by a car on city streets Tuesday night, police said.

At about 7 p.m., the boy and his grandmother were crossing the street near Del Monte Recreation Center when they were both struck by a vehicle making a left turn from Frontage Road onto Crestview Drive, Pittsburg police Lt. Ron Raman said.

The boy was badly hurt and rushed by helicopter to a nearby hospital, Raman said. He was stable Wednesday morning but no details of his injuries were released.

The grandmother was also hurt, but was able to walk to the ambulance that carried her to a hospital, Raman said.

The driver remained at the scene and was cooperative with police, Raman said. There was no immediate reason to believe drugs or alcohol had played a factor in the collision, he added.

The investigation is ongoing, Raman said.

Contact Sean Maher at 925-943-8013. Follow him on Twitter at twitter.com/OneSeanMaher.