In the week since the unarmed black 18-year-old Michael Brown was shot by a police officer, church pastors have joined those protesting on the streets of Ferguson, Missouri.

There is contention over whether the shooting on August 9 was racially motivated. Some accounts say that the teenager was shot by police officer Darren Wilson while he was surrendering, but police say that Brown assulted the officer before he was shot.

Since the shooting, some protests have become violent, resulting in smashed windows, looting and arson.

Many have been criticical of the agressive response from police, who fired tear gas and rubber bullets at peaceful protestors.

African Methodist Episcopal Church (AMEC) pastor Renita Lamkin was shot by a rubber bullet by riot police while she was attempting to mediate between the protestors and the police, the Huffington Post reported last week.

An Instagram photo shows a wound on Lamkin's stomach caused by the bullet.

Lamkin said her aim was for "everybody to go home. The police and the people." She added, "We're not here to fight the police. We're here to fight the system."

A photo in the Washington Post shows Rev Willis Johnson, pastor of Wellspring Church, Ferguson encouraging Joshua Wilson, 18, to protest peacefully and avoid arrest.

Johnson said in an interview with KUOW radio station that he wasn't trying to discourage the black teenager from protesting but to "affirm him".

"It's hard for people who are not there in it to understand why someone would channel or choose that mode to express themselves. I don't understand it fully, but what I do understand is what it means to be that angry," he said.

"People who are hurting need to be affirmed in their hurt; people who are angry need to be affirmed in their anger. Let me say it like this: I needed that as much as he needed that. We kept each other from harm's way and from doing something that we would need not to do," he added.

While there were signs of the protests calming down on Friday, tensions rose once again at the weekend, and the National Guard was called in on Sunday evening.

Protestors broke the state-imposed curfew and Police Captain Ron Johnson, in charge of the security operation, said protesters had shot at officers and thrown petrol bombs, the BBC reports.

A preliminary post-mortem showed that Michael Brown had been shot six times, including twice in the head.