An Illinois teenager who fatally shot two people and wounded a third amidst sometimes violent summer protests on the streets of Kenosha Wisconsin, has pleaded not guilty to charges including intentional homicide.

Kyle Rittenhouse, 18, entered his plea in a brief hearing conducted by teleconference.

Prosecutors say Rittenhouse, who is white, left his home in Antioch, Illinois, and travelled to Kenosha after learning of a call to protect businesses in the wake of the August 23 shooting by police of Jacob Blake.

Blake, a black man, was shot seven times in the back and left paralysed.

Rittenhouse opened fire with an assault-style rifle during protests two nights later, killing Joseph Rosenbaum and Anthony Huber and wounding Gaige Grosskreutz.

Rittenhouse has argued he fired in self-defence.

Conservatives have rallied around Rittenhouse, describing him as a patriot who took up arms to protect people and property, and raised enough money to make his bail.

Others see him as a domestic terrorist whose presence with a rifle incited protesters. Rittenhouse was 17 at the time of the shootings.

The Blake shooting happened three months after George Floyd died while being restrained by police officers in Minneapolis, which also was captured on bystander video and which sparked outrage and protests that spread across the United States and beyond.

The galvanised Black Lives Matter movement put a spotlight on inequitable policing and became a fault line in politics, with President Donald Trump criticising protesters and aggressively pressing a law-and-order message that he sought to capitalise on in Wisconsin and other swing states.