Thousands of protesters marched through downtown Chicago on Sunday in one of the city's largest demonstrations in years.

Protesters march through Chicago to NATO summit
Posted 21.05.2012 08:18:31 UTC
Updated 21.05.2012 08:18:31 UTC

The crowd expressed grievances about war, climate change and a wide range of other complaints as world leaders assembled for a NATO summit.

The protest, which for months had stirred worries about violence in the streets, drew together a broad assortment of participants, including peace activists joining with war veterans and people more focused on economic inequality.

But the diversity of opinions also sowed doubts about whether there were too many messages to be effective.

And some of the most enduring images of the event were likely to be from the end â€" when a small group of demonstrators clashed with a line of police who tried to keep them from the lakeside convention center where President Barack Obama was hosting the gathering.

The protesters tried to move east toward McCormick Place, with some hurling sticks and bottles at police. Officers responded by swinging their batons. The two sides were locked in a standoff for nearly two hours, with police blocking the protesters' path and the crowd refusing to leave. Some protesters had blood streaming down their faces.

Authorities were seen making arrests one by one and leading individual demonstrators away in handcuffs.

At the end of the march, police appeared to be using precisely the tactics Superintendent Garry McCarthy said they would â€" extracting individuals from the crowd and quickly getting them away from the rest of the demonstrators.

Police also used "sound cannons" to give orders to demonstrators and tried to relieve officers who had become fatigued to help prevent any escalation in violence.

The demonstrations unfolded just a day after three activists who traveled to Chicago for the summit were accused of manufacturing Molotov cocktails in a plot to attack Obama's campaign headquarters, Emanuel's home and other targets.