Protesters in Chicago plan more demonstrations a day after clashing with authorities outside the NATO summit.

Organizers from the Occupy Chicago movement are planning to demonstrate at the headquarters of aerospace giant Boeing.

At least 45 protesters were arrested Sunday when thousands took to the streets protesting the war in Afghanistan, economic inequality, and other issues.

The demonstrations were largely peaceful until late in the day, when some of the protesters tried to push through a line of police keeping them from the convention center where leaders and delegates from 50 countries were meeting.

Police in riot gear used batons to respond to the demonstrators after several protesters threw bottles and other objects at the officers. Four officers reportedly suffered minor injuries in the clashes.

Earlier, police said two men were in custody on charges of planning to make bombs for use during the NATO meetings.

Those arrests followed terrorism charges against three other men Saturday for possession of explosive devices. Police say the three plotted to attack President Barack Obama's campaign headquarters in Chicago, the home Mayor Rahm Emanuel, and other targets.