A demonstration in Calgary organized by an anti-racism group turned violent Saturday when they were confronted by white supremacists.

Two people suffered head injuries during melee when protesters began throwing projectiles. Police also arrested three people.

On Saturday morning, the Anti-Racist Action group met near Calgary's City Hall to commemorate the International Day to Eliminate Racial Discrimination.

But as the group marched along a downtown street around 3 p.m., a bus containing members of the Aryan Guard congregated in the same area.

In total, about 500 people were involved in the confrontation, which took place near a transit terminal and snared bus and train service in the area.

For the most part, police observed and built human walls between the two groups.

Both groups left the area around 4:30 p.m.

With files from CTV Calgary