Emergency services outside the festival in New Jersey

A suspect has been killed after a gunman opened fire at a 24-hour art and music festival, injuring around 20 people. 

Police described ‘chaos’ as the killer began shooting a little before 3am local time, leaving multiple people in need of hospital treatment.

Over a dozen people were injured by gunshots or in a stampede at Art All Night, a cultural event in Trenton, New Jersey overnight.

A 13-year-old boy was in a critical condition on Sunday night, along with three others.

Trenton police Lt. Darren Zappley said multiple people have been shot and were taken to the hospital, where some are in surgery.

He told media: ‘It’s very chaotic out here.’

Angelo Nicolo told ABC6: ‘All of a sudden, my brother goes to me, ‘You hear that gunfire?’

‘I go, ‘It sounds like fireworks’.

‘He said, ‘No, that’s gunfire’. Next thing you know, we turn around and everybody’s running down the street.

‘All hell broke loose.’

METRO GRAB - taken from ABC6 report no permission Trenton shooting Link to - http://6abc.com/shots-fired-at-trenton-arts-festival-several-injured/3612187/?sf191967369=1 ABC6
Emergency services at the scene (Picture: ABC)
METRO GRAB - taken from ABC6 report no permission Trenton shooting Link to - http://6abc.com/shots-fired-at-trenton-arts-festival-several-injured/3612187/?sf191967369=1 ABC6
The art festival is a popular community event held overnight (Picture: ABC)

He said that he and his brother were at the event when they heard loud popping sounds. He said people started running down the street.

‘I saw two police officers escort a guy that got shot in the leg, they bandaged him up and whisked him away,’ Nicolo said.

The event began Saturday afternoon and was scheduled to continue through the night and end Sunday afternoon. It typically draws thousands of people.

Organisers posted on Facebook that the remainder of the event had been cancelled, saying: ‘We’re very shocked. We’re deeply saddened.

‘Our hearts ache and our eyes are blurry but our dedication and resolve to building a better Trenton through community, creativity and inspiration will never fade. Not tonight. Not ever.’

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