Prosecutors have dropped charges against 20 protesters who blocked a key Toronto bridge as part of international climate demonstrations last month.

Crown attorneys told a Toronto court on Monday that it would not be in the public interest to pursue criminal charges against the protesters, who blocked the Bloor Viaduct for several hours on Oct. 7 as part of an international movement to spur urgent government action on climate change.

Some of the accused had expressed frustration at being charged for engaging in what they and police have described as a peaceful protest.

The Toronto chapter of the environmental group Extinction Rebellion said at the time of the demonstration that impeding traffic was a necessary, if disruptive, tactic.

Similar protests also took place in Halifax, Edmonton, Vancouver and other Canadian cities, while some European cities saw hundreds of people turn up for protests.

One of the Toronto protesters wore a cow jumpsuit to Monday's court appearance, while others removed plush cow and bull hats before the proceedings began as non-religious head wear is prohibited inside courtrooms.