A Canadian judge handed protesters at the G20 summit in Toronto a small victory today by restricting the use of a controversial sound cannon for crowd control.
The Ontario judge said that under current Toronto police guidelines, the so-called Long Range Acoustic Device - a super-high-volume loudspeaker - could cause hearing damage if used at certain levels and distances.
Toronto police said they would comply with an order to amend guidelines governing use of the sound cannon, specifically with regards to distance and volume limitations.
Police say the cannons, purchased in recent weeks, will be used for communication. The portable loudspeakers are also known as sonic guns because the volume can be turned up so high they can be used as weapons.
"I have concluded that a very real likelihood exists that demonstrators may suffer damage to their hearing from the proposed use of the Alert function at certain distances and volumes," Justice David Brown of the Ontario Superior Court wrote in his ruling.
Canada is spending about C$1 billion on security for two international summits this week, with much of that going to control thousands of protesters who use the events to drive demands to end global poverty and address climate change.
Today and tomorrow, leaders from the Group of Eight industrialised nations will meet in Huntsville, Ontario, about two hours' drive north of Toronto. The Group of 20 nations will then gather in Toronto tomorrow and Sunday.
Protests have already begun at both locations but have been mostly peaceful.
Several thousand marched in defence of indigenous rights in Toronto yesterday and more marches were scheduled for today.
Earlier this year, police at the Vancouver Olympic games disabled the Alert function on the devices so that they could only be used as loudspeakers.