A gang of around ten youths were caught on camera launching rockets and roman candles at rivals in the middle of a busy residential neighbourhood.
Footage of the dangerous action shows members of the gang lighting fireworks in their hands and aiming them towards one and other across a park.
The clip was captured near the Shepherdess Walk Park in Hoxton, London, on Saturday evening at around 8.30pm.
The footage resembled scenes of wizarding duels from the Harry Potter film series, where firework-like effects are fired towards characters.
The youths then take to the surrounding streets with the fireworks and continue to fire them directly at each other.
One of the gang members is even hit by one of the fireworks from close range.
Loud explosions can be heard on the video clip, as well as the sound of laughter from some members of the gang.
Witness James Castle, 38, was relaxing at home with his girlfriend, but reached for his phone to record the clip in “disbelief” after being disturbed by the noise outside his flat.
He said: “We were watching TV and heard loud explosions close by. My first reaction was to phone the police. They were showing a blatant disregard to the safety of themselves and members of the public.
“They were actually firing them directly at each other. It was extremely dangerous.”
He described seeing people “running” in the street as the gangs launched the explosives at each other across the open Shepherdess Walk Park.
He added: “My first thought was about how many people usually walk up and down the street.
“A lot of families live nearby. I was concerned for the welfare of the public. There were people running in the street.
“It’s just simply shocking that people would do that in the middle of the street.
“It did look like they were getting enjoyment out of it. It could have had a devastating impact on someone’s life.”
He recalls how at one point during the five-minute firework brawl, bushes near the park caught fire.
The fire service were called by a member of the public to extinguish the flames.