Ontario's police watchdog is investigating after a Hamilton police motorcycle and another driver's motorcycle collided on the Mountain Monday afternoon.

According to a press release from the Special Investigations Unit, a Hamilton officer on a motorcycle was trying to stop a man who was also on a motorcycle around 2:30 p.m.

Their motorcycles then collided near South Bend Road West and Upper James Street, the SIU says.

The man then ran off after the crash. Another officer tracked him down and arrested him in the area of West 1st Street and McElroy Road West, the SIU says.

The man was then taken to St. Joseph's Hospital for treatment of an arm injury.

The SIU says four investigators, two forensic investigators and one collision reconstructionist have been assigned to investigate the incident.

The SIU is mandated to investigate reports involving police where there has been death, serious injury or allegations of sexual assault.