CHICAGO (AP) — Thousands of demonstrators gathered Saturday afternoon in downtown Chicago, hours after protesters clashed overnight with police during a protest over the death of George Floyd, a handcuffed black man who died after a Minneapolis police officer pressed his knee into his neck for several minutes.

The crowd converged on Chicago's Loop for Saturday's protest march, during which at least one flag was burned, and some protesters climbed onto a bus and a lightpole and surrounded police officers.

The crowd began their demonstration at Chicago's federal plaza at 2 p.m. and began marching north about 90 minutes later, the Chicago Tribune reported.

In the evening, pictures tweeted by a Chicago Sun-Times photographer showed multiple Chicago police cars were damaged and several people were detained on the Near North Side.

Video sent out by another local reporter also showed police in tactical gear walking on a downtown street.

Saturday's demonstration came after Chicago officials, following overnight clashes with protesters, asked that additional protests remain peaceful. Demonstrations are expected throughout the weekend over Floyd's death.

Chicago police Superintendent David Brown said peaceful protests that began Friday afternoon turned more confrontational as the night wore on, resulting in 108 arrests. Protesters blocked traffic along major streets, threw bottles and other objects at police vehicles and shattered the windows of downtown businesses.

About a dozen squad cars were damaged and some officers suffered minor injuries, including a broken wrist.

The violence in Chicago and many other cities was sparked by anger over over Floyd’s death in Minneapolis on Monday, which was captured on cellphone video. It led to the firing Tuesday of the four police officers who were arresting Floyd for suspicion of passing a counterfeit bill and to third-degree murder and manslaughter charges being filed Friday against the officer who used his knee to pin Floyd down for more than eight minutes, even as Floyd pleaded for air and went limp.