This is what happened when white people carried guns in Ferguson

On the anniversary of unarmed black teenager Michael Brown's death at the hands of a police officer in Ferguson, Missouri, thousands of people gathered to honour his memory and to protest against ongoing police brutality directed at black people in the US.

The demonstrations have for the most part been peaceful, although marred by an incident late on Sunday night.

Reuters reports an 18-year-old man started shooting at four officers inside a police vehicle who returned fire, injuring the shooter. The city announced a state of emergency and curfew in an effort to curb any further violence.

Dozens of people were arrested for breaching the curfew, as well as offences such as throwing rocks and bottles, obstructing police movement and the "normal use of entrances". One group of men was arrested under suspicion of carrying weapons, which later proved to be groundless.

And while protesters spend the night in jail cells, some of them after false arrests, white people armed with assault rifles who call themselves the 'Oath Keepers' have been filmed patrolling the streets of the city:

At least three members of the 'Oath Keepers', wearing bulletproof vests and military-style fatigues, were seen in the suburb of St Louis suburb overnight on Monday.

The group self-identifies as patriots who are "formerly serving military, police, and first responders who pledge to fulfill the oath all military and police take to 'defend the Constitution against all enemies, foreign and domestic'" They are viewed as unhelpful vigilantes by citizens and police alike, and many people tried to ask them to leave:

While Missouri's 'open carry' law means it's technically legal to openly display your firearms in public, it is unclear whether the law still applies during a state of emergency - and many people have been quick to point out the hypocrisy of arresting unarmed black citizens while letting armed white people walk the streets freely.

More than 140 people have been arrested over the last few days, the vast majority of them black.

Protests around the city had begun to die down on Tuesday, after four consecutive nights of marches and demonstrations.

More: Two people shot by police during #BlackLivesMatter protest in Ferguson

More: In brief: What you need to know about the Ferguson grand jury decision