Rioters fired shots, hurled rocks and set buildings alight during violent clashes after a police officer shot and killed an armed man in the US city of Milwaukee.

City leaders appealed for calm after a mob of around 100 people took to the streets following the deadly shooting.

One officer was hit in the head by a brick thrown through a police car window, while a petrol station was set on fire.

An empty police vehicle was also targeted by arsonists.

Authorities said firefighters were initially unable to tackle the blazes because of gunfire.

Mayor Tom Barrett had called on parents of children at the scene of the protests to "get them home right now".

Alderman Ashanti Hamilton said: "Our city is in turmoil tonight."

He pledged to make the circumstances of the shooting public and urged people to "allow the process to work". 

Trouble flared after a 23-year-old man armed with a stolen handgun was shot during a foot chase.

Mayor Barrett said the man had been ordered to drop his weapon but he had failed to do so.

He added: "An officer fired several times. The individual was hit in the chest and hit in the arm. He was hit by two bullets. That individual has died."

Neither the race of the suspect nor the officer have been disclosed.

The shooting happened in one of the city's poorest areas, where the community is predominantly black.

The unrest is the latest in a series of disturbances to hit US cities, including Baton Rouge, Dallas, and Ferguson, Missouri, following fatal police shootings.

All of the previous incidents involved young black men, giving rise to the Black Lives Matter movement.