Michael Brown shooting: Violence erupts after police shoot second man amid calls for calm from Obama

Angry protests have continued in the US for days over the shooting

A crowd stages a protest (AP Photo/St. Louis Post-Dispatch, David Carson)

Violence erupted again on Tuesday night in Missouri as armed police clashed with protesters in angry demonstrations over the shooting of an unarmed black teenager.

The death of 18-year-old Michael Brown on Saturday has sparked days of unrest in the city of St Louis, despite calls for calm by Barack Obama and community leaders.

Around 250 demonstrators were stopped by police from entering the road where Mr Brown had been on the way to visit his grandmother in the suburb of Ferguson.

A wall of armed police formed a barricade across Florrisant Street, where protests had flared up the previous nights, leading to looting and vandalism by small groups on Sunday.

Officers ordered protesters to “get out of the road or face arrest” before firing teargas, rubber bullets and baton rounds into the crowd.

Photos showed SWAT teams in military-style uniforms pointing guns at protesters and some individuals were seen hurling missiles and teargas cannisters back at the police line.

Some raised their arms above their heads and repeated what has become a defining slogan: "Hands up, don't shoot."

As the crowds were dispersed shortly after midnight, another man was shot close to the scene of Mr Brown’s death.

Police said teams had been responding to reports of shots being fired and men armed with guns wearing ski masks.

He was shot while allegedly pointing a handgun at an officer, police said, and was in a critical condition in hospital.

President Obama promised a full investigation by the US Department of Justice into Mr Brown's death and the FBI has also stepped in.

"I know the events of the past few days have prompted strong passions," he said.

"I urge everyone in Ferguson, Missouri, and across the country, to remember this young man through reflection and understanding."

Friends and family of Brown held a peaceful church vigil on Tuesday night, after his father pleaded for an end to the violence. Standing with supporters, including the Reverend Al Sharpton, Michael Brown Sr. said he wanted justice for his son but wanted it "the right way."

"I need all of us to come together and do this right, the right way," he said, wearing a T-shirt showing his son's baby picture. "No violence."

Police officers keep watch while demonstrators (not pictured) protest the death of black teenager Michael Brown in Ferguson, Missouri (Reuters)

At another church gathering with dozens of clergy members and officials, the Governor of Missouri Jay Nixon urged calm “in the face of crisis".

“We stand together tonight, reeling from what feels like an old wound torn open afresh,” he said.

“A wound that hadn't quite healed right in the first place, and now the pain is just as searing as when the injury first occurred.”

Eyewitness accounts have contradicted the police department's account of events, which said Mr Brown was shot after a struggle for an officer's gun.

Dorian Johnson, 22, said he had been walking with his friend in the middle of the street when a police officer in a car reportedly told them to “get the f*** on the sidewalk”.

A struggle near the officer’s car followed, with Mr Johnson reporting that Mr Brown was shot at close range.

After being shot in the back as he tried to run away, he said his friend turned around with his hands up and said “I don’t have a gun, stop shooting!” but the officer reportedly shot him several more times.

Mr Johnson's version of events has been corroborated by several other eyewitness accounts, although police from Ferguson maintain that the teenager was killed following a struggle for the officer’s gun.

There is no security or police video footage of the incident, according to police.

Mr Brown's death has exposed deep racial and economic fault lines in the community.

Out of 53 officers in the Ferguson - a working class, mostly black suburb - only three are black and officials said the city has had trouble recruiting and retaining black officers.

The identity of the officer involved, who witnesses said was white, has not been revealed and is currently on paid leave for the investigation.

Ferguson police said they initially planned to release the name of the officer but decided to withhold if after officers received death threats.

Additional reporting by AP