A group of 600 people on Sunday stood in silence for four and a half minutes at the Michael Brown memorial in Ferguson, Missouri, to commemorate the slaying of the 18-year-old black young man by a white police officer exactly a year ago.

The length of time symbolized the four and a half hours that Michael Brown's body lay in the street after he was killed by Darren Wilson.

Brown's father, Michael Brown Sr., led a commemorative march, saying the anniversary brought back all the grief and raw emotions.

There were also various speeches and recitals of "slam poetry", a type of poetry with sharp intonation, first adopted by the African-American community in 1980s.

Activist Erica Paschel told Xinhua, "I'm out here to fight for what I believe in. I believe that justice needs to be served. I'm not going to just sit at home, and I feel like you're doing something once you're out here and doing actions."

"(I'm here to) reconnect, reaffirm why a revolution started out here, to remember that justice has still not been served, that Darren Wilson is still in denial that he killed a boy for walking, for jaywalking," Mamatay Smith said.

"Things are calming down and people are doing more positive things, positive protests, that's why I'm out here supporting today," said Jesse Spearman.

Melva Paschel said that media attention has made people lose sight of the fact that a family lost a child.

"Violence, looting, none of that is the answer. So I believe that the answer is, if we come together, we can get our voice to be heard," she said.

Police largely stayed away from the commemoration activities, in great contrast to last year, when they used armored personnel carriers, and SWAT operators with riot shields to cope with a spate of protests stirred up by Brown's death, some of which turned into riots.