PHOENIX (AP) — Authorities say a mountain biker rider is dead after collapsing on South Mountain Park trail in Phoenix.

The name of the 43-year-old man wasn't immediately released Sunday.

Phoenix and Tempe fire crews responded to calls about a biker collapsing on the trail.

Bystanders and other bike riders in the area performed CPR on the man until fire crews arrived, but authorities say he died.

The man reportedly had no major medical problems, but Phoenix police are investigating the death.