A gang of up to 30 youths – at least one brandishing a machete – caused a police alert at the Kingsgate centre in Huddersfield on Saturday.
Officers were called to the shopping complex at 3.30pm to reports of a gang brandishing weapons.
Police sent local officers and support officers armed with tasers to deal with what was described as a “dispute” between two gangs.
Eyewitnesses said at least one youth was armed with a machete and the gang stormed through House of Fraser and out into the car park where there was a confrontation in the car wash area.
It is not thought anyone was injured but a window in a door in the car park pay area was smashed.
Trader Mara Podolski said: “We saw a load of gang members, probably about 30 guys, running through past the shoppers.”
Another stallholder in the main shopping area, who did not want to be named, said: “All we’ve heard is that somebody was in the car park getting their car washed and some guys ran through up here and into the car park to have it out with them.
“One of them had a machete and the police were called. House of Fraser partially closed their shutters for a while and the police have taped off a door after the window was smashed and blood was left on it.”
A man who works in the car park car wash said: “There was a grey Ford here and the three men had left it to pay for parking. The next thing we know is that a man with a machete came down but I didn’t see what happened.”
Insp Tom Harrison, duty officer for West Yorkshire Police, said police attended and were treating the matter as a public order offence.
He said several youths were spoken to but no arrests were made.
He added that “no victim had come forward” so it was thought no-one had been injured.
He said there were reports that the youths were carrying “bladed weapons” and at least one had been seen with a knife.
He said the incident was all resolved within 20 minutes.
No-one from Kingsgate was available to comment.