The parents of the black teenager gunned down by police in Ferguson, Missouri, have rejected an apology by the city's top cop, saying he should be sacked and the white officer who shot their son arrested.

Michael Brown's mother, Lesley McSpadden, said "Yes" when asked if Chief Tom Jackson should be fired, and his father, Michael, said rather than an apology, they would rather see Officer Darren Wilson arrested for the death of their 18-year-old son on August 9, which sparked widespread rioting.

"An apology would be when Darren Wilson has handcuffs, processed and charged with murder," Mr Brown said.

The shooting of the unarmed teenager sparked days of violent protests and racial unrest in the predominantly black community.

Some residents and civil rights activists have said responding police officers were overly aggressive, noting their use of tear gas and surplus military vehicles and gear. The shooting and police response to the protests stoked a national discourse about police tactics and race.

Mr Brown called the looting that has been interspersed with the protests "disrespectful", but said: "First Amendment protesting? They have that right."

The First Amendment of the US Constitution guarantees such basic rights as freedom of speech and assembly.

"There's going to continue to be unrest until they do what should be done," Ms McSpadden added, referring to Ferguson officials.

Police say Michael was shot after a scuffle broke out when Officer Wilson told Michael and a friend to move out of the street and on to the pavement. Officer Wilson was pushed into his squad car and attacked, police say.

Some witnesses reported seeing Michael's arms in the air in an act of surrender. A post-mortem examination found he was shot at least six times.

Relatives denounced a video released by police, who say it shows Michael snatching cigars from a convenience store just before he was killed. In the video, the person said to be him is seen grabbing an assistant and forcefully pushing him into a display rack.

Mr Jackson last week released a video apology to the Brown family and the community, which is predominantly African-American, in which he acknowledged that Michael's body should have been removed from the street much sooner. The young man's body lay uncovered for more than four hours while police collected evidence.

But Ms McSpadden said: "I don't want words, I want action."

Michael's parents, wearing T-shirts with messages about their son, talked hesitantly about their emotions following their son's death. Ms McSpadden said she feels lost and helpless, and her life will never be normal again. "I have to find a new normal," she said.

"I'm empty," Mr Brown said. "There's nothing there any more. It's hard to fill that spot with other happiness."

Michael's parents are in Washington DC to meet politicians and lobby Congress to pass a law requiring police officers to wear cameras while dealing with the public.

They also called on the Justice Department to take over the criminal investigation into the shooting. The department is already investigating whether Michael's civil rights were violated and a county grand jury is considering whether to indict Officer Wilson.

"All of our eyes see the same thing, that it was wrong, an injustice. Why wouldn't they come back with an indictment?" Ms McSpadden said.

The parents also expressed anger at some Ferguson police officers who wore bracelets in support of Officer Wilson.

In a letter released on Friday, the Justice Department asked Mr Jackson to "confirm our understanding" that officers in the suburban St Louis County department won't wear "I am Darren Wilson" bracelets while on duty.

Ferguson residents complained about the black bracelets with white lettering this week at a meeting with federal officials. The Brown family's lawyer, Benjamin Crump, said the bracelets give an impression that the police lack impartiality in this case.

"It lets me know how they really feel about the situation, and the wrongness that they do," Ms McSpadden said.

Michael's parents talked with politicians during the Congressional Black Caucus' legislative conference weekend and plan to keep on lobbying.

Mr Brown called their efforts a fight for human rights. "They say that this is America, but we're not being treated like we're Americans. Our fight here is to just open other eyes and understand how we're feeling and try to get something done about it," he said.

Ms McSpadden said her son was taught how to respect his elders.

"I taught my son respect for a policeman, for you, for this woman, for anybody, so if he felt like he was doing nothing wrong, which I don't believe he was, why would he be in fear of him?" she said. "You're not supposed to fear the police."

Meanwhile President Barack Obama told the Congressional Black Caucus Foundation the mistrust of policing exposed after the Ferguson shooting had a corrosive effect on all of America, not just on black communities.

Speaking at the group's annual awards dinner in Washington, Mr Obama said mistrust harmed places that needed law enforcement the most.

He also said it mades people reluctant to go to the police and scarred the hearts of all children.

Mr Obama said a programme launched this year to help make young minority men's lives better would be expanded.

A Ferguson officer was shot after encountering two suspects at a community centre who fired at him during a foot chase last night. St Louis County police chief Jon Belmar said the policeman was shot in the arm.

He said the officer fired shots in return but that police had no indication that either suspect was shot. A search is under way for the suspects.

Mr Belmar said he did not think the shooting was related to two separate protests that were going on around the same time.