PORTLAND, Ore. -- Hikers discovered what appear to be human bones while walking along a Southwest Portland trail on Sunday afternoon.

Officers responded to the report and were led by the hikers to the bones on the side of a trail in the River View Natural Area west of Macadam Avenue.

Homicide detectives, forensic evidence criminalists and the Oregon State Medical Examiner were called to the scene after officers reported the bones appeared to be human.

The bones will be transported to the Oregon State Crime Lab for further examination. At this point, the age, race, gender of the bones has not been determined. It is also unclear if there was any criminal activity.

The trail will be closed for a few hours Sunday night until the investigation is finished.