The anarchists protesters of the G-20 summit forced the police to throw canister of pepper spray and smoke at them. Some of the protesters had responded by throwing rocks and rolling trash bins.

The peak of the protesting occurs when President Obama and first lady Mischelle Obama arrived for the meeting with the leaders of the world’s major economies.

The police start to clash on Pittsburg streets when the protesters tried to pass through from an outlying neighborhood toward the convention center.

The hundreds of protesters were wearing dark clothes, and bandanas Some of them are carrying black flags while others put on their helmets and safety goggles.