Dozens of fires burned and 130 police officers were injured after “international left-wing extremists” rampaged through Hamburg’s streets in opposition to the G20 Summit Thursday night.

Masked demonstrators threw bottles and stones, blocked streets, and smashed and burnt cars in Thursday night’s so-called “Welcome To Hell” demonstration. Footage from Friday morning showed numerous fires still burning in the streets and thick black smoke hanging over large parts of the city.

Police were forced to deploy water cannons, tear gas, and riot control tactics, but could not prevent the destruction as they found themselves underprepared and short-staffed.

Early morning in Hamburg as the G20 summit gets under way https://t.co/Xl83INF8ME pic.twitter.com/KE3GuWEf56 — BBC News (World) (@BBCWorld) July 7, 2017

In total, 130 police officers were injured, WELT reports, with 12 unable to continue doing their jobs. Three officers required treatment in hospital.

The injured included police helicopter pilots who sustained eye injuries when laser pointers were directed at them. “Police are still being attacked,” a spokesman for Hamburg’s police told AFP.

The clashes took place around just one and a half miles from the site of the summit.

Hamburg police were forced to request further support from all German federal states because of the extent of the disorder, with many coming from Berlin and Mecklenburg-Vorpommern.

A senior police officer told WELT: “We can only hope that the rumours disappear that international left-wing extremists want to attack the capital [Berlin] in parallel. Because these indications have existed for quite some time.”

So far, some 20,000 policemen from all over Germany have been deployed in the city to safeguard the meeting of world leaders.

Police estimate that 8,000 violent individuals are currently in the city, with 12,000 attending Thursday night’s protest. The biggest demonstration, with up to 100,000 participants, is expected on Saturday.

Thursday night’s violence erupted less than an hour after Chancellor Angela Merkel met with President Donald Trump and the event descended into chaos at around midnight.

VIDEO: Police in Hamburg use water cannons on protesters as G20 summit gets under way – BBCpic.twitter.com/JPObqPqaXj — Conflict News (@Conflicts) July 7, 2017