A tense standoff between protesters and the police in Ferguson, Missouri turned chaotic Sunday night when gun shots rang out and a young black man lay critically injured in the street.The incident began just before midnight local time when approximately 40-50 shots were fired during a short space of time in a gun battle between two groups on West Florissant Avenue, the site of protests over Michael Brown's death last year.Police called for an ambulance and the 18-year-old was eventually taken to a local hospital in critical "unstable" condition, where he underwent surgery. His father later said the shooting victim was "real close" with Brown.