Thousands of anti-war protesters marched through the streets of Chicago Sunday, taking their discontent to world leaders assembled for a NATO summit.

The Sunday protest was largely peaceful until the end, when some of the demonstrators tried to push through a line of police keeping them from the lakeside convention center where leaders and delegates from 50 countries are meeting.

Some protesters refused repeated warnings from police to disperse after the peaceful demonstrations ended. The situation turned somewhat violent when some of the protesters threw bottles and other objects at the police. Several arrests were made. Police swung batons and dragged away several people.

The protest followed several smaller demonstrations over the previous two days. Most have been peaceful, but police said two men were in custody, accused of planning to make Molotov cocktails for use during the NATO meetings.

On Saturday, three men were charged with with terrorism for possession of explosive devices. Police say they plotted to use the devices in an attack on President Barack Obama's campaign headquarters in Chicago, the home of the city's mayor, Rahm Emanuel, and other targets.