KINGMAN, Ariz. (AP) — Authorities say two Kingman men have been seriously injured in a crash involving four motorcycles.

Kingman police say one of the men suffered life-threatening head and internal injuries while another man also remains hospitalized in serious condition with internal injuries that aren't life-threatening.

They say four motorcyclists were travelling as a group Saturday morning in Kingman when a 43-year-old man made a lane change and struck a 59-year-old rider.

A 52-year-old man driving a third motorcycle in the group struck the non-helmeted first rider, causing him to lose control and crash.

The 29-year-old fourth cyclist also went down while trying to avoid the other crashes.

The fourth motorcyclist also wasn't wearing a helmet but suffered only lacerations and didn't need hospital treatment.

Police say alcohol or other impairment isn't suspected.