Video purportedly shows US police shoot stabbing suspect in the street

Warning this video contains disturbing images viewers may find distressing

Video has emerged that purportedly shows the moment US police officers shoot a stabbing suspect in broad daylight.

San Francisco police were called to the city's Bayview neighbourhood after a man said he was stabbed in the shoulder.

The video, filmed from a bus window, shows several officers surround a man who was carrying a knife, which police believed to be the weapon used in the stabbing. After attempting to apprehend the man, with firearms drawn, gun shots are heard as the person filming seeks cover.

A voice can be heard shouting "put it down" before shots are fired.

In a press release, San Francisco Police reported that both a "Bean Bag" gun and pepper spray had previously been used on the suspect to no apparent effect.

As the suspect, still carrying the knife, continued to walk up the street towards an officer, 'fearing serious injury or death', officers started shooting.

Police said they had seen the video and 'Investigators will continue to canvas the area for more.'