Brown's father pleads for calm at funeral

The father of the slain US teenager appealed for calm as mourners gathered for the funeral.

Tracy Martin, the father of Trayvon Martin who was killed by a neighborhood watch volunteer in 2012, attends Peace Fest in Forest Park on August 24  in St Louis, Missouri.

FERGUSON - The father of Michael Brown, the black teenager who was shot dead by a white police officer in Ferguson, Missouri, on 9 August, appealed for calm as family, politicians and activists gathered for the funeral on Monday following weeks of unrest.

The sometimes violent protests have spawned headlines around the world and have focused attention on racial issues in the United States. Local police have been criticised for mass arrests and the use of heavy-handed tactics and military gear.

"All I want tomorrow is peace while we lay our son to rest," Michael Brown Sr said at a rally against police violence that he led on Sunday with civil rights leader Reverend Al Sharpton.

"Please, that's all I ask," he told the crowd of hundreds, including the parents of Trayvon Martin, the Florida teenager shot dead by a neighbourhood watch volunteer in 2012.

Sharpton, who will also attend the funeral, said: "We don't want anything tomorrow that will defile Michael Brown's name."

Authorities remained braced for a possible flare-up around the funeral, although clashes between protesters and police had significantly decreased by midweek and the National Guard began a gradual withdrawal from the St Louis suburb on Friday.

The White House said it was sending three presidential aides to the service at a St Louis Baptist church and a large turnout was expected both inside and outside.

Hours before the 10 am funeral, rights leader Reverend Jesse Jackson told Reuters: "I think people will be under control. I think people will leave ... feeling inspired."

"Ferguson is a part of a bigger national urban cancer. This crisis is a metaphor for the urban American crisis," he said.

On Sunday evening, only a handful of people gathered at the site of the recent protests, greatly outnumbered by a visible but unobtrusive police presence.

Speaking on CBS's Face the Nation, Democratic Representative Lacy Clay of Missouri, who is slated to speak at the funeral, said he had promised Brown's parents he would push for a transparent investigation into his death.

"I'm more concerned that if we do not get to the truth and get to what actually happened and bring justice to this situation, then there's going to be a problem in the streets," he said.

A grand jury began hearing evidence on Wednesday, a process the county prosecutor said could take until mid-October.

"The real question is how quickly the killer has to pay the price," Jackson said early on Monday.