TORONTO (CP) - Ontario's provincial police commissioner says protesters will be held accountable for their behaviour on Friday's aboriginal day of action.

Most of the scheduled events are peaceful marches, but there are concerns some protesters may resort to illegal measures such as highway or railway blockades.

One notable protester is Mohawk Shawn Brant, who organized the blockade of a CN rail line in April and has threatened to do the same again, as well as blockade Highway 401.

Commissioner Julian Fantino says he thinks Brant is a "one-off," and warns he will be held accountable for his actions.

Brant is currently out on bail on charges of mischief, disobeying a court order and breach of recognizance in connection with the 30-hour April blockade.

Fantino says his force has had to deal with similar issues in the past, and that any response will be a measured one.