This is why a midwest town in the US looks like a warzone

Since the shooting of an unarmed black teenager by an, as-yet, unnamed police officer, the St Louis suburb of Ferguson in Missouri has resembled nothing short of a battleground.

Pictures of heavily armed police advancing on unarmed demonstrators, officers dismounting from armoured vehicles and residents fleeing tear gas have been seen around the world.

This military-grade equipment was not made available to the Ferguson police department at the start of the unrest following 18-year-old Michael Brown's death on Saturday, however, it was in fact gathering dust at St Louis county HQ.

Officers in the town are just one of hundreds of law enforcement agencies to have taken advantage of a federal programme called 1033, which stems from a 1990 law (the National Defence Authorisation Act) passed by Congress to help law enforcement agencies combat drug-related activities.

It is now mainly used by the Department of Defence to pass on surplus military equipment, and in total $4.3billion worth of arms and vehicles have been acquired by 8,000 police forces and other departments in the US, including $449million in 2013 alone.

The Defence Logistics Agency is responsible for these "disposition services" but does not reveal precisely which forces have acquired what equipment.

But, for example, Fairmont police department, which serves a population of 7,000 in northern Georgia, has bought - at a greatly reduced rate - 17,145 items from the Pentagon, while 50 officers in Oxford, Alabama, have $3million worth of military equipment at their disposal, including M-16s and an armoured vehicle.

The state patrol in landlocked Nebraska meanwhile has three amphibious eight-wheeled tanks.

The gradual militarisation of police in the US is something to be extremely concerned about, claims Radley Balko, Washington Post reporter and author of Rise of the Warrior Cop.

"It is a mentality that sees the people they are supposed to be serving not as citizens with rights but as potential threats," he told NBC News.

"If you look at the racial makeup of Ferguson, Missouri, it is about 67 per cent black. 52 of the 55 police officers at the Ferguson police department are white."

More: This is what police officers now look like in Ferguson, Missouri