It is meant to be a protest against gun violence but shots have been fired in Ferguson, Missouri, United States, during a march to mark the first anniversary of the killing of unarmed black teenager, Michael Brown.

Police has confirmed that an officer was “involved in a shooting after coming under heavy gunfire,” and that “two unmarked cars took shots”.

According to media report, eyewitnesses said that one injured person was seen lying on the ground.

The shooting of the 18-year-old last year by white Police officer, Darren Wilson, triggered a national protest movement against racial bias by the police across America.

As part of the commemoration earlier on Sunday, hundreds of people observed a four-and-half minute silence at the spot where Michael Brown was killed, representing the number of hours that his body lay in the street, unattended.