A girl under five years old who was seriously injured in a three-vehicle collision on Highway 401 in Ajax last Friday has died in hospital.

On Nov. 27, emergency crews were called to the eastbound lanes of the highway near Westney Road shortly after 5:30 p.m.

Ontario Provincial Police said an adult and two children were injured and were taken to hospital.

One of the children died on Wednesday, police said. The other child and the adult remain in hospital.

The OPP are not releasing the name of the child.

The cause of the crash is under investigation.