Family and supporters of Michael Brown today celebrated the life of the black teenager killed by a white officer in Ferguson, Missouri, in a music-filled funeral service ringing with calls for peace and police reforms.

The teen’s body lay in a black and gold casket at the Friendly Temple Missionary Baptist Church.

It was topped with the St Louis Cardinals baseball cap he was wearing when he was killed on 9 August.

People jammed inside the modern red-brick church and gathered outside on Dr Martin Luther King Drive in St Louis for the celebration, a markedly different scene from the violent protests that rocked the St Louis suburb of Ferguson after the police shooting of the unarmed 18-year-old.             

The slaying has focused global attention on the state of race relations in the United States.

Police and demonstrators in Ferguson clashed nightly for more than a week, with authorities coming under fire for mass arrests and the use of heavy-handed tactics and military gear.

The teenager's coffin was surrounded by photos of him as a child, graduating from school and smiling in his baseball cap.             

Spirited gospel music by a choir and horn players filled the sanctuary, and mourners clapped their hands and danced in the aisles.

Readings from the Bible were met with whoops and cheers.

Printed in a program for the service were letters from hisparents to their late son.

A letter by Michael Brown Sr read: "I always told you I would never let nothing happen to you and that's what hurts so much, that I couldn't protect you."

A grand jury has begun hearing evidence in the shooting and the US Justice Department has opened its own investigation.             

In a eulogy for Michael, civil rights activist Al Sharpton demanded a fair and impartial investigation into the shooting and an end to police brutality.             

"Michael Brown does not want to be remembered for riots," Mr Sharpton said.

"He wants to be remembered as the one that made America deal with how we're going to police in the United States."             

He also called on the black community to end the kind of street violence and looting that cast Ferguson in a negative light.

"We have to be outraged for our disrespect for each other," he said. "Some of us act like the definition of blackness is how low you can go.

"Blackness has never been about being a gangster or a thug. Blackness was no matter how low we was pushed down, we rose up anyhow," he said.

Family and friends rose to speak as well, recalling Michael’s nicknames of "Gentle Giant" and "Big Mike."

Pastor Charles Ewing, who is Michael’s uncle, recalled Michael once telling him: "One day the whole world will know my name."

"Michael Brown's blood is crying from the ground, crying for vengeance, crying for justice," Pastor Ewing said.

Outside, under the hot midday sun, the police presence was heavy but relaxed.

Authorities had braced for a possible flare-up, although clashes between protesters and police have waned significantly in recent days.

The crowd repeated the now-familiar "Hands up, don't shoot," which protesters have chanted in the streets of Ferguson.

In differing accounts of the shooting, police have said the teen struggled with the officer who shot and killed him.

But some witnesses say he held up his hands and was surrendering when he was shot multiple times in the head and chest.