Riot police had to lockdown an estate in London and clear youths with swords, machetes and bats off the streets.
One man was stabbed and a car was attacked by a mob of up to 30 armed with bats and hammers after it was chased down the street.
Police have reportedly found and seized a large amount of weapons.
Youths clashed with armed police at Stamford Hill, in north London, an area known for its Hasidic community, the largest concentration of Haredi Jews in Europe.
Jake McKeown said on Twitter there are reports that the car's passenger was holding a gun.
It is alleged to be the second successive night of violence in the suburb, which is very close to Finsbury Park, where police say was a terrorist attack on Muslims on Monday.
Shomrim N.E. London, a "proactive neighbourhood watch group", said one man was stabbed, with two stabbed after an illegal rave at neighbouring suburb Woodberry Down the previous night.
Holding shields and forming a line, officers urged the youths to leave the area and marched down streets to cordon off a large area.
The London Metropolitan Police helicopter was also brought in.
On Twitter, a user named Merlin Jobst wrote: "cops with dogs and riot gear cordoning off every entrance to my estate on Stamford hill. loads more inside. apparently for a block party".
It is also understood a man suffered serious head injuries after a robbery outside a petrol station with the suspects fleeing yesterday. The victim is in a critical condition.
A London Metropolitan Police spokesman told the Daily Star.
"Additional officers were called to Stamford Hill estate to reports of a fight between a large group.
"One person was found at the scene suffering form a stab wound.
"He has been taken to hospital and we are awaiting an update on his condition."
"Lots of machetes and swords were ditched and hidden by youths in the surrounding streets as police responded to violence," Shomrim N.E. London reported.