Around 20,000 police officers from all of Germany's 16 states have been deployed on the streets of Hamburg to help contain protests against the G20 summit. They will be facing off against up to 100,000 protesters, including an estimated 8,000 who police say are prepared to use violence.

Dozens of police were injured in clashes on Thursday (6 July) as protesters damaged cars, set other objects ablaze and threw bottles in clashes that lasted until midnight. Police said that at least 76 officers were hurt, one of whom had to be taken to a hospital with an eye injury after a firework exploded in front of him. Officers repeatedly used water cannons, as well as pepper spray and batons, amid the clashes with violent protesters.

G20 protests Hamburg Welcome to Hell
Protesters erect burning barricades in front of the Rote Flora left-wing centre in HamburgAlexander Koerner/Getty Images
G20 protests Hamburg Welcome to Hell
German riot police clash with protesters during the demonstrations during the G20 summit in HamburgFabrizio Bensch/Reuters
G20 protests Hamburg Welcome to Hell
Riot police move in through the smoke from a smoke bombOdd Andersen/AFP
G20 protests Hamburg Welcome to Hell
An anti-G20 protester waves a flag in front of burning rubbish outside the Rote Flora buildingKai Pfaffenbach/Reuters
G20 protests Hamburg Welcome to Hell
A police water cannon sprays a protester during the demonstrationsFabrizio Bensch/Reuters
G20 protests Hamburg Welcome to Hell
A protester lights a flare after the Welcome to Hell rally against the G20 summit in HamburgChristof Stache/AFP
G20 protests Hamburg Welcome to Hell
A man throws furniture onto burning pile of bins in front of the Rote Flora left-wing centreOdd Andersen/AFP
G20 protests Hamburg Welcome to Hell
Police officers walk in front of a fire started by protestersChristof Stache/AFP
G20 protests Hamburg Welcome to Hell
A protester holds a flare during a protest ahead the G20 summit in HamburgKai Pfaffenbach/Reuters
G20 protests Hamburg Welcome to Hell
An anti-G20 protester gestures in front of a water cannonKai Pfaffenbach/Reuters
G20 protests Hamburg Welcome to Hell
German riot police use water cannons against protesters during the demonstrationsPawel Kopczynski/Reuters
G20 protests Hamburg Welcome to Hell
German riot police use water cannons against protesters during the demonstrationsPawel Kopczynski/Reuters
G20 protests Hamburg Welcome to Hell
German riot police use water cannons against protestersFabrizio Bensch/Reuters
G20 protests Hamburg Welcome to Hell
Police gather at Hamburg harbour prior to the Welcome to Hell anti-G20 protest marchThomas Lohnes/Getty Images
G20 protests Hamburg Welcome to Hell
Police gather at Hamburg harbour prior to the Welcome to Hell anti-G20 protest marchThomas Lohnes/Getty Images
G20 protests Hamburg Welcome to Hell
A demonstrator shouts at the police during the Welcome to Hell anti-G20 protest marchThomas Lohnes/Getty Images
G20 protests Hamburg Welcome to Hell
An anti G-20 placard reads "The Punch is coming"Kai Pfaffenbach/Reuters
G20 protests Hamburg Welcome to Hell
G20 protests Hamburg Welcome to Hell
Protesters hold their hands during the demonstration during the G20 summit in HamburgHannibal Hanschke/Reuters
G20 protests Hamburg Welcome to Hell
Riot police use water cannon against protestersChristof Stache/AFP
G20 protests Hamburg Welcome to Hell
Demonstrator stand in the water jet from police water cannonThomas Lohnes/Getty Images
G20 protests Hamburg Welcome to Hell
Police stand in front of 'Welcome to Hell' anti-G20 protestersThomas Lohnes/Getty Images
G20 protests Hamburg Welcome to Hell
A woman holds up a handful of fake US currency during the Welcome to Hell anti-G20 protestLeon Neal/Getty Images
G20 protests Hamburg Welcome to Hell
A protester shouts as riot police use water cannon trucksChristof Stache/AFP
G20 protests Hamburg Welcome to Hell
Protestors are sprayed by police water cannonsLeon Neal/Getty Images
G20 protests Hamburg Welcome to Hell
Protesters throw beer bottles as they shield themselves from water cannon sprayJohn MacDougall/AFP
G20 protests Hamburg Welcome to Hell
A man washes another man's eye after suspected tear gas useLeon Neal/Getty Images
G20 protests Hamburg Welcome to Hell
A man gives a one-fingered salute as paramedics carry him awayLeon Neal/Getty Images
G20 protests Hamburg Welcome to Hell
Protesters hold up a banner as they take part in the "Welcome to Hell" protestAlexander Koerner/Getty Images
G20 protests Hamburg Welcome to Hell
A firefighter sprays water over burnt out vehiclesFabrizio Bensch/Reuters
G20 protests Hamburg Welcome to Hell
The interior of a burnt-out car is seen as firefighters work in the backgroundHannibal Hanschke/Reuters
G20 protests Hamburg Welcome to Hell
Protestors who are blocking a street are surrounded by German policePawel Kopczynski/Reuters
G20 protests Hamburg Welcome to Hell