World leaders are gathering in Pittsburgh for the G20 summit under the shadow of a police crackdown on protesters in the streets. Heavily-armed riot police are out in force all over the city, using tear gas, stun grenades, smoke canisters, and sound cannons, which direct extremely loud shrill sounds. This is believed to be the first time sound cannons have been publicly used in the United States. Democracy Now! producer Steve Martinez reports from the streets of Pittsburgh.

Tune in on Monday for Steve’s full report